After the jam

So I didn't win in the tech jam, but congrats to the winners.     

Added some tasty gibs when creatures die, depending on the mass of the creature.

Fixed a lot of navigation problems when things are just out of reach.

Fixed things not floating in water, although creatures still don't really understand it (except frogs, they know all).

Added stats for killed creatures and a single achievement so I can see if anyone actually went down there.