Feature: Background Audio Playback

Adding, importing, and using the audio libraries from Slick-Util so we can have beautiful, beautiful background music.

I have added a preliminary song that I found on the 'net which is free to use (comes from http://www.tannerhelland.com/music-directory/ ).

Sound files can be WAV or OGG. OGG is compressed like MP3, WAV is not, so we should use as many OGG's as possible when adding more sounds.