stagefright: Support for offloading MPEG2 audio

Change-Id: I8e76e9f98139c8f5170ee2bcc39682e5cba9dfa8
Fix M3UParser relative path handling.

Bug: 16017037
Change-Id: Ibfff99387fb5b3e721144a2b3f9174092d785137
M3UParser: check for NULL before setting meta data

Bug:16351654
Change-Id: I64e9510f719b220471522b4d78a9b00a98bda772
Fix Externally reported security issue

bug: 12724697
Change-Id: I57f37dbb3b01c0c3d3256be67c395352dd6ada13
RTSP: Return the buffers in source side while the source is disconnected

There is a race condition, some buffers are held by the source
because of the poor network environment. If the client tries to flush at
this time, the flush operation will be blocked because not all the buffers
are returned to the client.
At this time, sometimes, the source will be disconnected from the server,
then these buffers held by the source won't be returned any more.
Without this patch, flush operation maybe won't finish, and blocks
other operations, causing ANR.

Change-Id: I19581498d17a29b637d5468932438ea862e1c7ff