Add gitignore
Update tools version
Add jarRelease task
Update README.md
Merge pull request #17 from rejasupotaro/dev

Thanks!
Add language to Format (+other misc fix).
Merge branch 'dev' of https://github.com/google/ExoPlayer into dev
Merge branch 'dev' of persistent-https://github.com/google/ExoPlayer into dev
Finish painful bytes/sec -> bits/sec conversion.
Fix integer variant of library version.
Make DefaultWebmExtractor handle cues and format independently.

* Remove concept of being prepared by simply reporting if format
and/or cues are known.
* Allow replacement of format and/or cues later in the stream.
* Initialization and index segments can be parsed independently
of one another but must be in order due to internal WebM dependencies.
* Let seekTo() work even when cues are unknown.
Don't call doSomeWork if we're preparing
Add CacheDataSource.Listener.
Changes around renderer readiness and extraction.

- Make MediaCodecTrackRenderer.isReady more permissive.
  This largely fixes #21
- Bring WebmExtractor closer to FragmentedMp4Extractor.
  The two will probably be placed under a common interface
  fairly soon, which will allow significant code
  deduplication.
Optimize some CodecCounter inefficiency.

1. Use ints rather than longs.
2. Remove some counters that dont seem hugely useful.
3. Replace use of volatile with explicit method calls that
   cause a memory barrier. This is a lot more efficient than
   using volatile because it can be invoked only once per
   doSomeWork.
Minor cleanup.

- Add constants class. Currently housing a single lonely variable,
which is used generally throughout the library, and so no longer
nicely fits into a specific class.

- Rename a few other constants to add clear units.

- Made minor tweak to ExoPlayer documentation.
Simplify parsing of encryption data + support SENC boxes.

Issue: #4
Optimize out quite a few allocations in FragmentedMp4Parser.
Don't release AudioTrack unless we have to.
Remove unnecessary SuppressWarning annotations.