New player type values for Open SL ES

Define new player types to describe the two types of AudioPlayer
  in OpenSL ES: those with a buffer queue source, those that
  play from a given URI or FD.
Add a warning in the interface description of AudioService
  that changes should be reflected in the native interface too.

Test: make, NDK tests to follow
Bug: 30955183
Change-Id: I7b530ea6e3b13f238f662ce8b9612e7df574a9c5