Bug 910996 - Move MP3FrameParser out of B2G specific code, so it can be used on other platforms. r=padenot

--HG--
rename : content/media/omx/MP3FrameParser.cpp => content/media/MP3FrameParser.cpp
rename : content/media/omx/MP3FrameParser.h => content/media/MP3FrameParser.h
Bug 910966 - Use MP3FrameParser in DirectShow's SourceFilter, to more accurately determine the offset of the first MP3 frame. This enables us to only pass the MP3 data into DirectShow, which can't handle large ID3v2 tags. r=padenot