Bug 882677 - Part 1: Dispatch loaded and error events to the HTMLTrackElement. r=cpearce
Bug 882677 - Part 2: Handle ParsingErrors from vtt.js correctly. r=cpearce

* Update vtt.js to the newest version which has the capability
of reporting back ParserErrors.
* Update the update-vtt.js script a bit as well since
the symbols that it exports have changed a bit since the last import.
Some of the general information it outputs has since changed as well
like where the repo exists.
* Update WebVTTListener to set the track readiness state
to 'failed to load' if the WebVTT file is not loaded correctly.
Bug 882677 - Part 3: Set Track::ReadyState after flushing the parser. r=cpearce

The parser might report errors during the flush call so we can't check and set the ReadyState of the track yet.
Bug 882677 - Part 4: TextTrack::ReadyState should be set to 'error' if loading the stream fails. r=cpearce
Bug 882677 - Part 5: Add track element tests. r=cpearce
Bug 893397 - Add FreeBSD support for NeckoWifi. r=ted, r=jdm
Bug 912627 - Remove spurious assertion. r=cpearce
Bug 973761 - [WebRTC] Check device capabilities (HW codec and Android ver) before enabling vp8 hardware acceleration on Fennec. r=bjacob, r=gcp
Bug 978479 - Remove flipped quad texture from mQuadVBO. r=bjacob