Group collision-checks.
Enable collisions between minions with world and minions with other
minions.
Hard-code minions, collide with world bounds and platforms.
Merge branch 'music' of https://github.com/mayermi/turtle into mayermi-music

Conflicts:
	js/models/minion.js
	js/states/play-state.js
	turtle.js
happy-loop works without pause