Created base Moveable class

This provides the ability to instruct something to move with a direction
as well as applying forceMoves to the object

Just remember to call super() from inside the update of any derived
classes
Merge branch 'master' of https://github.com/ginja85/LudumDare31

Conflicts:
	src/scripts/game.coffee
Add player damage knockback physics

When the player comes into contact with a monster he should be pushed
back, take damage and be invunervable for a period.

Also monsters should be immovable and not float around wierdly!