Added GroundMonster, Updated Monster/Player

How do the monster/groundmonster files look?  I _think_ that's the way to do it, and then for every other type of monster I'm basically just copying the groundmonster class and changing a variable or two (then passing it off to whomever to alter the image and animation and everything else).

If this is correct, I can get all the other monster and item classes done by Friday.