First 5.1 support for MediaForkCLI. Uses a new command line option of "-6 --surround...

First 5.1 support for MediaForkCLI.  Uses a new command line option of "-6 --surround" to preserve 5.1 audio as a 6-channel AAC track when using FAAC for audio.  For example: ./MediaForkCLI -i /dev/disk5 -o penguins_test.mp4 -t 1 -c 1 -6 -e ffmpeg -E faac -d -R 44.1

For now, this assumes that all selected audio tracks have the same audio format.  Since only one audio track works at present, this isn't a disaster.

git-svn-id: svn://svn.handbrake.fr/HandBrake/branches/0.8.0_beta2_5.1@309 b64f7644-9d1e-0410-96f1-a4d463321fa5