Add collision detection.

Ooops. This is all one commit. Fuckery!
Merge pull request #5 from variousauthors/collision

Collision
Merge branch 'master' into megaman_controls

Conflicts:
	player.lua
Added dashing to falling transition
[WIP] Some state machine trouble!

- A mid-air Jump is causing the player to rocket downwards.
- There is a problem with key mashing not being distinct