Add audio class and prepare sound/wave banks

The intro music cue has been provisionally added, but will need to be tweaked when I can merge with Kory's impending commit the latest game-state code. At that point I'll be able to add all the rest of the cues.
Merge branch 'Collisions' of https://github.com/ethanjohnson89/comp446-project2 into Collisions

Conflicts:
	Crate/Crate.cpp (resolved)