Tribbles

Please don't bite my head off, I accidentally closed it. Not ever used gitHub before.

This is to add Tribbles to the game. They are more fully documented on the forum post: http://www.ss13.eu/phpbb/viewtopic.php?f=12&t=2275

They breed up to 50 in the world, the can be neutered with a scalpel and un-neutered with a cautery.

Included is the code for a lab-cage containing a tribble, my suggested format for distribution in-game.