New background animation

it doesn't do much for now but it will. I have plans for 2 types of backgrounds; ones like this one where the objects occupy the same space as the track, and the other is a completely separate view behind the track. The latter allows for more to happen because it doesn't interfere with the foreground but takes a significant cpu processing hit. Both types can be loaded from an external folder so users can make their own backgrounds (feature for later)

This background can be turned off from the application menu (menu -> kraken -> release?) and it is disabled by default. Turning it off and on only takes effect after loading a song.

I've also added volume controls for the song and the song menu preview. The volume of the preview is a percentage of the song volume so it is never louder than the actual song. There is also a slider for the Crowd volume, but it does not do anything at the moment.