SDK / exoplayer

* this fixes a bug when switching from HE-AAC 22050Hz to AAC 44100Hz (the AudioTrack was not reset and we were trying to send a bad number of bytes, triggering a "AudioTrack.write() called with invalid size" error)
* this also improves quality switches, making it almost seamless

gradle plugin 0.14.4 fixes

fixes broken import statements

Issue: #158

MediaCodecTrackRenderer: Avoid excessive garbage generation

- Unredact internal error ids.
- Move images.

Looking up a long in a HashSet<Long> auto boxes the long and leaves
it for the GC. As decodeOnly is relatively infrequent it's much
better to do a simple linear search in a List<Long>. That way
we can avoid boxing every incoming time stamp value. In the general
case this will be linear searching in an empty list, a very fast
operation.

Signed-off-by: Jonas Larsson <jonas@hallerud.se>

AudioTrack contains the portions of MediaCodecAudioTrackRenderer that handle the
platform AudioTrack instance, including synchronization (playback position
smoothing), non-blocking writes and releasing.

This refactoring should not affect the behavior of audio playback, and is in
preparation for adding an Ac3PassthroughAudioTrackRenderer that will use the
AudioTrack.

Remove implicit back-reference from playback thread to player.

Merge dev-l into dev, now L SDK is released.

dev -> dev-l

dev -> dev-l

Use largeHeap in demo app