Added sound capability to the game. [WIP]

Licensing issues: The test soundtracks are taken from http://smf.cataclysmdda.com/index.php?topic=1483.msg16972#msg16972 but there are no explicit licenses anywhere?! Why host a music submission contest if you don't ask people to submit content under the appropriate license? =/

Other than that, this should be almost good to go in. I'm just tracking down an obnoxious bug where only the first item of a playlist is ever played.