add support for raw vc1 bitstreams
sample- http://samples.mplayerhq.hu/V-codecs/WVC1/rtvc1.vc1

To play the file in stagefright we had to use "vc1" as file extension, otherwise
stagefright does nothing. I use LegacySniffFFMPEG func to handle it. the url will be
"android-source:0x416b91a0|file:/storage/emulated/legacy/Movies/x86/rtvc1.vc1"
fix crash when ffmpeg video port notify setting change event.
We don't notify event until "outQueue.size() == kNumOutputBuffers"

crash log:
I/SoftFFmpegVideo( 4196): ffmpeg video port setting change event(352x144)->(352x288).
F/OMXCodec( 4196): frameworks/av/media/libstagefright/OMXCodec.cpp:3285 CHECK(info->mStatus == OWNED_BY_US || info->mStatus == OWNED_BY_NATIVE_WINDOW) failed.
F/libc    ( 4196): Fatal signal 11 (SIGSEGV) at 0xdeadbaad (code=1), thread 4241 (OMXCallbackDisp)