reorganize SoundPool and JetPlayer code.

Reorganize SoundPool and JetPlayer code to be ready for the
creation of libmedia_native.

Split SoundPool between libsoundpool (JNI) and libmedia(sound pool implementation).
Remove dependencies on nativehelper/jni.h from JetPlayer.

Change-Id: I130c6014173b714329929dd82c5dfb70b757a610
9 files changed