Adding music to the build

Once we received the audio for the game, I put implemented the background music for the Main Menu, Level select, and base level. Playing with the background music makes the game seem more complete and it really sets in that the semester is almost over and we will no longer be working on Alternalien.

While importing, Crushers inspector items were missing. When punching, the game would fail and I was required to add the audio in, since it was a part of the coroutine.