Changes in version 0.2.4.26 - 2015-03-17
Tor 0.2.4.26 includes an updated list of directory authorities. It
also backports a couple of stability and security bugfixes from 0.2.5
and beyond.

o Directory authority changes:
- Remove turtles as a directory authority.
- Add longclaw as a new (v3) directory authority. This implements
ticket 13296. This keeps the directory authority count at 9.
- The directory authority Faravahar has a new IP address. This
closes ticket 14487.

o Major bugfixes (exit node stability, also in 0.2.6.3-alpha):
- Fix an assertion failure that could occur under high DNS load.
Fixes bug 14129; bugfix on Tor 0.0.7rc1. Found by "jowr";
diagnosed and fixed by "cypherpunks".

o Major bugfixes (relay, stability, possible security, also in 0.2.6.4-rc):
- Fix a bug that could lead to a relay crashing with an assertion
failure if a buffer of exactly the wrong layout was passed to
buf_pullup() at exactly the wrong time. Fixes bug 15083; bugfix on
0.2.0.10-alpha. Patch from 'cypherpunks'.
- Do not assert if the 'data' pointer on a buffer is advanced to the
very end of the buffer; log a BUG message instead. Only assert if
it is past that point. Fixes bug 15083; bugfix on 0.2.0.10-alpha.

o Minor features (geoip):
- Update geoip to the March 3 2015 Maxmind GeoLite2 Country database.
- Update geoip6 to the March 3 2015 Maxmind GeoLite2
Country database.

Changes in version 0.2.5.11 - 2015-03-17
Tor 0.2.5.11 is the second stable release in the 0.2.5 series.

It backports several bugfixes from the 0.2.6 branch, including a
couple of medium-level security fixes for relays and exit nodes.
It also updates the list of directory authorities.

o Directory authority changes:
- Remove turtles as a directory authority.
- Add longclaw as a new (v3) directory authority. This implements
ticket 13296. This keeps the directory authority count at 9.
- The directory authority Faravahar has a new IP address. This
closes ticket 14487.

o Major bugfixes (crash, OSX, security):
- Fix a remote denial-of-service opportunity caused by a bug in
OSX's _strlcat_chk() function. Fixes bug 15205; bug first appeared
in OSX 10.9.

o Major bugfixes (relay, stability, possible security):
- Fix a bug that could lead to a relay crashing with an assertion
failure if a buffer of exactly the wrong layout was passed to
buf_pullup() at exactly the wrong time. Fixes bug 15083; bugfix on
0.2.0.10-alpha. Patch from 'cypherpunks'.
- Do not assert if the 'data' pointer on a buffer is advanced to the
very end of the buffer; log a BUG message instead. Only assert if
it is past that point. Fixes bug 15083; bugfix on 0.2.0.10-alpha.

o Major bugfixes (exit node stability):
- Fix an assertion failure that could occur under high DNS load.
Fixes bug 14129; bugfix on Tor 0.0.7rc1. Found by "jowr";
diagnosed and fixed by "cypherpunks".

o Major bugfixes (Linux seccomp2 sandbox):
- Upon receiving sighup with the seccomp2 sandbox enabled, do not
crash during attempts to call wait4. Fixes bug 15088; bugfix on
0.2.5.1-alpha. Patch from "sanic".

o Minor features (controller):
- New "GETINFO bw-event-cache" to get information about recent
bandwidth events. Closes ticket 14128. Useful for controllers to
get recent bandwidth history after the fix for ticket 13988.

o Minor features (geoip):
- Update geoip to the March 3 2015 Maxmind GeoLite2 Country database.
- Update geoip6 to the March 3 2015 Maxmind GeoLite2
Country database.

o Minor bugfixes (client, automapping):
- Avoid crashing on torrc lines for VirtualAddrNetworkIPv[4|6] when
no value follows the option. Fixes bug 14142; bugfix on
0.2.4.7-alpha. Patch by "teor".
- Fix a memory leak when using AutomapHostsOnResolve. Fixes bug
14195; bugfix on 0.1.0.1-rc.

o Minor bugfixes (compilation):
- Build without warnings with the stock OpenSSL srtp.h header, which
has a duplicate declaration of SSL_get_selected_srtp_profile().
Fixes bug 14220; this is OpenSSL's bug, not ours.

o Minor bugfixes (directory authority):
- Allow directory authorities to fetch more data from one another if
they find themselves missing lots of votes. Previously, they had
been bumping against the 10 MB queued data limit. Fixes bug 14261;
bugfix on 0.1.2.5-alpha.
- Enlarge the buffer to read bwauth generated files to avoid an
issue when parsing the file in dirserv_read_measured_bandwidths().
Fixes bug 14125; bugfix on 0.2.2.1-alpha.

o Minor bugfixes (statistics):
- Increase period over which bandwidth observations are aggregated
from 15 minutes to 4 hours. Fixes bug 13988; bugfix on 0.0.8pre1.

o Minor bugfixes (preventative security, C safety):
- When reading a hexadecimal, base-32, or base-64 encoded value from
a string, always overwrite the whole output buffer. This prevents
some bugs where we would look at (but fortunately, not reveal)
uninitialized memory on the stack. Fixes bug 14013; bugfix on all
versions of Tor.

Changes in version 0.2.6.5-rc - 2015-03-18
Tor 0.2.6.5-rc is the second and (hopefully) last release candidate in
the 0.2.6. It fixes a small number of bugs found in 0.2.6.4-rc.

o Major bugfixes (client):
- Avoid crashing when making certain configuration option changes on
clients. Fixes bug 15245; bugfix on 0.2.6.3-alpha. Reported
by "anonym".

o Major bugfixes (pluggable transports):
- Initialize the extended OR Port authentication cookie before
launching pluggable transports. This prevents a race condition
that occured when server-side pluggable transports would cache the
authentication cookie before it has been (re)generated. Fixes bug
15240; bugfix on 0.2.5.1-alpha.

o Major bugfixes (portability):
- Do not crash on startup when running on Solaris. Fixes a bug
related to our fix for 9495; bugfix on 0.2.6.1-alpha. Reported
by "ruebezahl".

o Minor features (heartbeat):
- On relays, report how many connections we negotiated using each
version of the Tor link protocols. This information will let us
know if removing support for very old versions of the Tor
protocols is harming the network. Closes ticket 15212.

o Code simplification and refactoring:
- Refactor main loop to extract the 'loop' part. This makes it
easier to run Tor under Shadow. Closes ticket 15176.

Tor Browser 4.0.5 -- Mar 23 2015
* All Platforms
* Update Firefox to 31.5.3esr
* Update Tor to 0.2.5.11
* Update NoScript to 2.6.9.19

Tor Browser 4.0.6 -- Mar 31 2015
* All Platforms
* Update Firefox to 31.6.0esr
* Update meek to 0.16
* Update OpenSSL to 1.0.1m

Tor Browser 4.5a5 -- Mar 31 2015
* All Platforms
* Update Firefox to 31.6.0esr
* Update OpenSSL to 1.0.1m
* Update Tor to 0.2.6.6
* Update NoScript to 2.6.9.19
* Update HTTPS-Everywhere to 5.0
* Update meek to 0.16
* Update Tor Launcher to 0.2.7.3
* Bug 13983: Directory search path fix for Tor Messanger+TorBirdy
* Update Torbutton to 1.9.1.0
* Bug 9387: "Security Slider 1.0"
* Include descriptions and tooltip hints for security levels
* Notify users that the security slider exists
* Flip slider so that "low" is on the bottom
* Make use of new SVG and MathML prefs
* Bug 13766: Set a 10 minute circuit lifespan for non-content requests
* Bug 15460: Ensure FTP urls use content-window circuit isolation
* Bug 13650: Clip initial window height to 1000px
* Bug 14429: Ensure windows can only be resized to 200x100px multiples
* Bug 15334: Display Cookie Protections menu if disk records are enabled
* Bug 14324: Show HS circuit in Tor circuit display
* Bug 15086: Handle RTL text in Tor circuit display
* Bug 15085: Fix about:tor RTL text alignment problems
* Bug 10216: Add a pref to disable the local tor control port test
* Bug 14937: Show meek and flashproxy bridges in tor circuit display
* Bugs 13891+15207: Fix exceptions/errors in circuit display with bridges
* Bug 13019: Change locale hiding pref to boolean
* Bug 7255: Warn users about maximizing windows
* Bug 14631: Improve profile access error msgs (strings).
* Pluggable Transport Dependency Updates:
* Bug 15448: Use golang 1.4.2 for meek and obs4proxy
* Bug 15265: Switch go.net repo to golang.org/x/net
* Bug 14937: Hard-code meek and flashproxy node fingerprints
* Bug 13019: Prevent Javascript from leaking system locale
* Bug 10280: Improved fix to prevent loading plugins into address space
* Bug 15406: Only include addons in incremental updates if they actually update
* Bug 15029: Don't prompt to include missing plugins
* Bug 12827: Create preference to disable SVG images (for security slider)
* Bug 13548: Create preference to disable MathML (for security slider)
* Bug 14631: Improve startup error messages for filesystem permissions issues
* Bug 15482: Don't allow circuits to change while a site is in use
* Linux
* Bug 13375: Create a hybrid GUI/desktop/shell launcher wrapper
* Bug 12468: Only print/write log messages if launched with --debug
* Windows
* Bug 3861: Begin signing Tor Browser for Windows the Windows way
* Bug 15201: Disable 'runas Administrator' codepaths in updater
* Bug 14688: Create shortcuts to desktop and start menu by default (optional)

Changes in version 0.2.4.27 - 2015-04-06
Tor 0.2.4.27 backports two fixes from 0.2.6.7 for security issues that
could be used by an attacker to crash hidden services, or crash clients
visiting hidden services. Hidden services should upgrade as soon as
possible; clients should upgrade whenever packages become available.

This release also backports a simple improvement to make hidden
services a bit less vulnerable to denial-of-service attacks.

o Major bugfixes (security, hidden service):
- Fix an issue that would allow a malicious client to trigger an
assertion failure and halt a hidden service. Fixes bug 15600;
bugfix on 0.2.1.6-alpha. Reported by "disgleirio".
- Fix a bug that could cause a client to crash with an assertion
failure when parsing a malformed hidden service descriptor. Fixes
bug 15601; bugfix on 0.2.1.5-alpha. Found by "DonnchaC".

o Minor features (DoS-resistance, hidden service):
- Introduction points no longer allow multiple INTRODUCE1 cells to
arrive on the same circuit. This should make it more expensive for
attackers to overwhelm hidden services with introductions.
Resolves ticket 15515.

hanges in version 0.2.5.12 - 2015-04-06
Tor 0.2.5.12 backports two fixes from 0.2.6.7 for security issues that
could be used by an attacker to crash hidden services, or crash clients
visiting hidden services. Hidden services should upgrade as soon as
possible; clients should upgrade whenever packages become available.

This release also backports a simple improvement to make hidden
services a bit less vulnerable to denial-of-service attacks.

o Major bugfixes (security, hidden service):
- Fix an issue that would allow a malicious client to trigger an
assertion failure and halt a hidden service. Fixes bug 15600;
bugfix on 0.2.1.6-alpha. Reported by "disgleirio".
- Fix a bug that could cause a client to crash with an assertion
failure when parsing a malformed hidden service descriptor. Fixes
bug 15601; bugfix on 0.2.1.5-alpha. Found by "DonnchaC".

o Minor features (DoS-resistance, hidden service):
- Introduction points no longer allow multiple INTRODUCE1 cells to
arrive on the same circuit. This should make it more expensive for
attackers to overwhelm hidden services with introductions.
Resolves ticket 15515.

Tor Browser 4.5 -- Apr 28 2015
* All Platforms
* Update Tor to 0.2.6.7 with additional patches:
* Bug 15482: Reset timestamp_dirty each time a SOCKSAuth circuit is used
* Update NoScript to 2.6.9.22
* Update HTTPS-Everywhere to 5.0.3
* Bug 15689: Resume building HTTPS-Everywhere from git tags
* Update meek to 0.17
* Update obfs4proxy to 0.0.5
* Update Tor Launcher to 0.2.7.4
* Bug 15704: Do not enable network if wizard is opened
* Bug 11879: Stop bootstrap if Cancel or Open Settings is clicked
* Bug 13576: Don't strip "bridge" from the middle of bridge lines
* Bug 15657: Display the host:port of any connection faiures in bootstrap
* Update Torbutton to 1.9.2.2
* Bug 15562: Bind SharedWorkers to thirdparty pref
* Bug 15533: Restore default security level when restoring defaults
* Bug 15510: Close Tor Circuit UI control port connections on New Identity
* Bug 15472: Make node text black in circuit status UI
* Bug 15502: Wipe blob URIs on New Identity
* Bug 15795: Some security slider prefs do not trigger custom checkbox
* Bug 14429: Disable automatic window resizing for now
* Bug 4100: Raise HTTP Keep-Alive back to 115 second default
* Bug 13875: Spoof window.devicePixelRatio to avoid DPI fingerprinting
* Bug 15411: Remove old (and unused) cacheDomain cache isolation mechanism
* Bugs 14716+13254: Fix issues with HTTP Auth usage and TLS connection info display
* Bug 15502: Isolate blob URI scope to URL domain; block WebWorker access
* Bug 15794: Crash on some pages with SVG images if SVG is disabled
* Bug 15562: Disable Javascript SharedWorkers due to third party tracking
* Bug 15757: Disable Mozilla video statistics API extensions
* Bug 15758: Disable Device Sensor APIs
* Linux
* Bug 15747: Improve start-tor-browser argument handling
* Bug 15672: Provide desktop app registration+unregistration for Linux
* Windows
* Bug 15539: Make installer exe signatures reproducibly removable
* Bug 10761: Fix instances of shutdown crashes

Changes in version 0.2.7.1-alpha - 2015-05-12
Tor 0.2.7.1-alpha is the first alpha release in its series. It
includes numerous small features and bugfixes against previous Tor
versions, and numerous small infrastructure improvements. The most
notable features are several new ways for controllers to interact with
the hidden services subsystem.

o New system requirements:
- Tor no longer includes workarounds to support Libevent versions
before 1.3e. Libevent 2.0 or later is recommended. Closes
ticket 15248.

o Major features (controller):
- Add the ADD_ONION and DEL_ONION commands that allow the creation
and management of hidden services via the controller. Closes
ticket 6411.
- New "GETINFO onions/current" and "GETINFO onions/detached"
commands to get information about hidden services created via the
controller. Part of ticket 6411.
- New HSFETCH command to launch a request for a hidden service
descriptor. Closes ticket 14847.
- New HSPOST command to upload a hidden service descriptor. Closes
ticket 3523. Patch by "DonnchaC".

o Major bugfixes (hidden services):
- Revert commit that made directory authorities assign the HSDir
flag to relay without a DirPort; this was bad because such relays
can't handle BEGIN_DIR cells. Fixes bug 15850; bugfix
on tor-0.2.6.3-alpha.

o Minor features (clock-jump tolerance):
- Recover better when our clock jumps back many hours, like might
happen for Tails or Whonix users who start with a very wrong
hardware clock, use Tor to discover a more accurate time, and then
fix their clock. Resolves part of ticket 8766.

o Minor features (command-line interface):
- Make --hash-password imply --hush to prevent unnecessary noise.
Closes ticket 15542. Patch from "cypherpunks".
- Print a warning whenever we find a relative file path being used
as torrc option. Resolves issue 14018.

o Minor features (controller):
- Add DirAuthority lines for default directory authorities to the
output of the "GETINFO config/defaults" command if not already
present. Implements ticket 14840.
- Controllers can now use "GETINFO hs/client/desc/id/..." to
retrieve items from the client's hidden service descriptor cache.
Closes ticket 14845.
- Implement a new controller command "GETINFO status/fresh-relay-
descs" to fetch a descriptor/extrainfo pair that was generated on
demand just for the controller's use. Implements ticket 14784.

o Minor features (DoS-resistance):
- Make it harder for attackers to overload hidden services with
introductions, by blocking multiple introduction requests on the
same circuit. Resolves ticket 15515.

o Minor features (geoip):
- Update geoip to the April 8 2015 Maxmind GeoLite2 Country database.
- Update geoip6 to the April 8 2015 Maxmind GeoLite2
Country database.

o Minor features (HS popularity countermeasure):
- To avoid leaking HS popularity, don't cycle the introduction point
when we've handled a fixed number of INTRODUCE2 cells but instead
cycle it when a random number of introductions is reached, thus
making it more difficult for an attacker to find out the amount of
clients that have used the introduction point for a specific HS.
Closes ticket 15745.

o Minor features (logging):
- Include the Tor version in all LD_BUG log messages, since people
tend to cut and paste those into the bugtracker. Implements
ticket 15026.

o Minor features (pluggable transports):
- When launching managed pluggable transports on Linux systems,
attempt to have the kernel deliver a SIGTERM on tor exit if the
pluggable transport process is still running. Resolves
ticket 15471.
- When launching managed pluggable transports, setup a valid open
stdin in the child process that can be used to detect if tor has
terminated. The "TOR_PT_EXIT_ON_STDIN_CLOSE" environment variable
can be used by implementations to detect this new behavior.
Resolves ticket 15435.

o Minor features (testing):
- Add a test to verify that the compiler does not eliminate our
memwipe() implementation. Closes ticket 15377.
- Add make rule `check-changes` to verify the format of changes
files. Closes ticket 15180.
- Add unit tests for control_event_is_interesting(). Add a compile-
time check that the number of events doesn't exceed the capacity
of control_event_t.event_mask. Closes ticket 15431, checks for
bugs similar to 13085. Patch by "teor".
- Command-line argument tests moved to Stem. Resolves ticket 14806.
- Integrate the ntor, backtrace, and zero-length keys tests into the
automake test suite. Closes ticket 15344.
- Remove assertions during builds to determine Tor's test coverage.
We don't want to trigger these even in assertions, so including
them artificially makes our branch coverage look worse than it is.
This patch provides the new test-stem-full and coverage-html-full
configure options. Implements ticket 15400.

o Minor bugfixes (build):
- Improve out-of-tree builds by making non-standard rules work and
clean up additional files and directories. Fixes bug 15053; bugfix
on 0.2.7.0-alpha.

o Minor bugfixes (command-line interface):
- When "--quiet" is provided along with "--validate-config", do not
write anything to stdout on success. Fixes bug 14994; bugfix
on 0.2.3.3-alpha.
- When complaining about bad arguments to "--dump-config", use
stderr, not stdout.

o Minor bugfixes (configuration, unit tests):
- Only add the default fallback directories when the DirAuthorities,
AlternateDirAuthority, and FallbackDir directory config options
are set to their defaults. The default fallback directory list is
currently empty, this fix will only change tor's behavior when it
has default fallback directories. Includes unit tests for
consider_adding_dir_servers(). Fixes bug 15642; bugfix on
90f6071d8dc0 in 0.2.4.7-alpha. Patch by "teor".

o Minor bugfixes (correctness):
- For correctness, avoid modifying a constant string in
handle_control_postdescriptor. Fixes bug 15546; bugfix
on 0.1.1.16-rc.
- Remove side-effects from tor_assert() calls. This was harmless,
because we never disable assertions, but it is bad style and
unnecessary. Fixes bug 15211; bugfix on 0.2.5.5, 0.2.2.36,
and 0.2.0.10.

o Minor bugfixes (hidden service):
- Fix an out-of-bounds read when parsing invalid INTRODUCE2 cells on
a client authorized hidden service. Fixes bug 15823; bugfix
on 0.2.1.6-alpha.
- Remove an extraneous newline character from the end of hidden
service descriptors. Fixes bug 15296; bugfix on 0.2.0.10-alpha.

o Minor bugfixes (interface):
- Print usage information for --dump-config when it is used without
an argument. Also, fix the error message to use different wording
and add newline at the end. Fixes bug 15541; bugfix
on 0.2.5.1-alpha.

o Minor bugfixes (logs):
- When building Tor under Clang, do not include an extra set of
parentheses in log messages that include function names. Fixes bug
15269; bugfix on every released version of Tor when compiled with
recent enough Clang.

o Minor bugfixes (network):
- When attempting to use fallback technique for network interface
lookup, disregard loopback and multicast addresses since they are
unsuitable for public communications.

o Minor bugfixes (statistics):
- Disregard the ConnDirectionStatistics torrc options when Tor is
not a relay since in that mode of operation no sensible data is
being collected and because Tor might run into measurement hiccups
when running as a client for some time, then becoming a relay.
Fixes bug 15604; bugfix on 0.2.2.35.

o Minor bugfixes (test networks):
- When self-testing reachability, use ExtendAllowPrivateAddresses to
determine if local/private addresses imply reachability. The
previous fix used TestingTorNetwork, which implies
ExtendAllowPrivateAddresses, but this excluded rare configurations
where ExtendAllowPrivateAddresses is set but TestingTorNetwork is
not. Fixes bug 15771; bugfix on 0.2.6.1-alpha. Patch by "teor",
issue discovered by CJ Ess.

o Minor bugfixes (testing):
- Check for matching value in server response in ntor_ref.py. Fixes
bug 15591; bugfix on 0.2.4.8-alpha. Reported and fixed
by "joelanders".
- Set the severity correctly when testing
get_interface_addresses_ifaddrs() and
get_interface_addresses_win32(), so that the tests fail gracefully
instead of triggering an assertion. Fixes bug 15759; bugfix on
0.2.6.3-alpha. Reported by Nicolas Derive.

o Code simplification and refactoring:
- Move the hacky fallback code out of get_interface_address6() into
separate function and get it covered with unit-tests. Resolves
ticket 14710.
- Refactor hidden service client-side cache lookup to intelligently
report its various failure cases, and disentangle failure cases
involving a lack of introduction points. Closes ticket 14391.
- Use our own Base64 encoder instead of OpenSSL's, to allow more
control over the output. Part of ticket 15652.

o Documentation:
- Improve the descriptions of statistics-related torrc options in
the manpage to describe rationale and possible uses cases. Fixes
issue 15550.
- Improve the layout and formatting of ./configure --help messages.
Closes ticket 15024. Patch from "cypherpunks".
- Standardize on the term "server descriptor" in the manual page.
Previously, we had used "router descriptor", "server descriptor",
and "relay descriptor" interchangeably. Part of ticket 14987.

o Removed code:
- Remove `USE_OPENSSL_BASE64` and the corresponding fallback code
and always use the internal Base64 decoder. The internal decoder
has been part of tor since tor-0.2.0.10-alpha, and no one should
be using the OpenSSL one. Part of ticket 15652.
- Remove the 'tor_strclear()' function; use memwipe() instead.
Closes ticket 14922.

o Removed features:
- Remove the (seldom-used) DynamicDHGroups feature. For anti-
fingerprinting we now recommend pluggable transports; for forward-
secrecy in TLS, we now use the P-256 group. Closes ticket 13736.
- Remove the undocumented "--digests" command-line option. It
complicated our build process, caused subtle build issues on
multiple platforms, and is now redundant since we started
including git version identifiers. Closes ticket 14742.
- Tor no longer contains checks for ancient directory cache versions
that didn't know about microdescriptors.
- Tor no longer contains workarounds for stat files generated by
super-old versions of Tor that didn't choose guards sensibly.

Tor Browser 4.5.1 -- May 12 2015
* All Platforms
* Update Firefox to 31.7.0esr
* Update meek to 0.18
* Update Tor Launcher to 0.2.7.5
* Translation updates only
* Update Torbutton to 1.9.2.3
* Bug 15837: Show descriptions if unchecking custom mode
* Bug 15927: Force update of the NoScript UI when changing security level
* Bug 15915: Hide circuit display if it is disabled.
* Translation updates
* Bug 15945: Disable NoScript's ClearClick protection for now
* Bug 15933: Isolate by base (top-level) domain name instead of FQDN
* Bug 15857: Fix file descriptor leak in updater that caused update failures
* Bug 15899: Fix errors with downloading and displaying PDFs
* Windows
* Bug 15872: Fix meek pluggable transport startup issue with Windows 7
* Build System
* Bug 15947: Support Ubuntu 14.04 LXC hosts via LXC_EXECUTE=lxc-execute env var
* Bugs 15921+15922: Fix build errors during Mozilla Tryserver builds

Tor Browser 5.0a1 -- May 14 2015
* All Platforms
* Update Firefox to 31.7.0esr
* Update meek to 0.18
* Update Tor Launcher to 0.2.7.5
* Translation updates only
* Update Torbutton to 1.9.2.5
* Bug 15837: Show descriptions if unchecking custom mode
* Bug 15927: Force update of the NoScript UI when changing security level
* Bug 15915: Hide circuit display if it is disabled.
* Bug 14429: Improved automatic window resizing
* Translation updates
* Bug 15945: Disable NoScript's ClearClick protection for now
* Bug 15933: Isolate by base (top-level) domain name instead of FQDN
* Bug 15857: Fix file descriptor leak in updater that caused update failures
* Bug 15899: Fix errors with downloading and displaying PDFs
* Bug 15773: Enable ICU on OS X
* Bug 1517: Reduce precision of time for Javascript
* Bug 13670: Ensure OCSP & favicons respect URL bar domain isolation
* Bug 13875: Improve the spoofing of window.devicePixelRatio
* Windows
* Bug 15872: Fix meek pluggable transport startup issue with Windows 7
* Build System
* Bug 15947: Support Ubuntu 14.04 LXC hosts via LXC_EXECUTE=lxc-execute env var
* Bugs 15921+15922: Fix build errors during Mozilla Tryserver builds