libmediaplayerservice: Add new player for DASH

- Add new player factory to support dash playback.
- DASH urls end with .mpd. When media player receives
  an url with .mpd, it will use new factory to instantiate the player
  to be used for supporting DASH playback.

Change-Id: I69e5a08fb2baf89d97b1e0711dbe52a8b1c39c29
ACodec: Support for dynamic port reconfig

- On port settings changed first flush output port
- Move ACodec to new state called FlushingOutputState
- Flush all output buffers, wait till all decoded buffers
  are rendered
- Then disable output port, and allocate output buffers
  with new resolution, and reset native window

Change-Id: Iafa266371ed2a87b909fbcb4eeae6b64208df617