DTS Postpro integration (for frameworks/av)

Adds DTS Postpro support in <root>/frameworks/av

Change-Id: I46edfb41571574ffa52c3a3f301cc003f914b00a
libmedia: Add support for LCH tones

- Add the INCALL_MUSIC flag for tracks
  created for INCALL_MUSIC stream.
- Adding tones to the ToneGenerator that are
  to be used for Local Call Hold.

Change-Id: If4092630ec67b11fd2844d0218639a2c5ae6b687
stagefright: provide a custom key to prefer adaptive playback

Provide a custom key "prefer-adaptive-playback" that can be
set in MediaFormat by java apps or by Native players to
prefer adaptive-playback over dynamic buffering

Change-Id: Ic02fc9f1d68fd9803ec154498a86e2537efcce85