* This is a rework of the session callback API which previously
lived in the framework due to JNI usage. This has been split out
and cleaned up for CMSDK.
* The JNI library lives on the server side, and the app-level
callback has been changed to a protected broadcast. This allows
us to wake up registered services when these events occur.
* Additionally, we support listing all active audio sessions.
* Also brings some JNI love/hate over to CMSDK.
Change-Id: I31c293943474419e3db088bb7ffab75f7440ac0f