JAudioTrack: Add 14 methods

This CL adds following methods in JAudioTrack:
 - frameCount / channelCount
 - getPosition
 - setAuxEffectSendLevel / attachAuxEffect
 - setVolume (2 different versions)
 - start / pause / flush / isPlaying / stopped
 - getSampleRate
 - format

Test: build successfully
Change-Id: I790acca4405f41a94fbe14daf5824e82d1d67b4c