Corrected issue of poison fog zombie explosions appearing in wrong spot. Still not sure why zombie matrons detonate upon spawn if a matron has died before it. There must be a shared variable somewhere, but I can't imagine where. Also added "type" variable to the Zombie class to check for the zombie's type. This is only used in one place for the moment. Before, tiny zombies would only appear after all other unborn zombies had spawned, so I changed it so that it checks the unborn list in each update for tiny zombies and adds them all at once.