ACodec: Add video codec fallback logic

- Check while onAllocate if codec is capable of handling video
  resolution. If not fallback\retry other capable components in the
  list

Change-Id: I3203275be23651dbd9ad7a7397526ac601a3350a
audioflinger: Fix cleanup of asynccallback thread

AsyncCallbackThread will not be spawned if the output
profile does not support non-blocking output or if the HAL does not
support set_callback API.

Add a check for validity of callback thread object before deleting it.

Change-Id: I3943f80abba3fd7f18fbfd6190bb884f773772b5
libstagefright: Fix in AudioPlayer media time mapping

- Use seektime as the play position when player is still
  seeking.

Change-Id: Id92a07e3291280b17b83d53ff2e218acc3ee6020