Add cook demucing, change rm demuxer so that it reorders audio packets
before sending them to the decoder, and send minimum decodeable sized
packets; pass only real codec extradata fo the decoder
Fix 28_8 decoder for the new demuxer strategy


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@4726 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b