[2/2] quartz: Add a libavformat based MPEG demuxer.

[Chris Robinson]

I wouldn't recommend this patch as being very safe. Having dealt with ffmpeg, 
my experience has been that it's ABI is not stable (the .so version number 
increments often, forcing recompilations). And when trying to update to new 
lib versions, things sometimes mysteriously break.

Ultimately, FFmpeg is better off as a "built-in" code base. A project wishing 
to use it should pick a version and include it, and not rely on it externally.