Minor edits

I changed InputProcessor to PlayerController. I also added even more
stuff to the original objects. I think I just changed Zombie. I added a
direction and a frame. I use frame to store the number of frames since
the last time I updated the zombie's actions. This is so that I can
update a zombie's movement every second instead of every frame. The
direction variable is so that the zombie remembers the direction it was
walking and can continue walking in that direction in between updates to
its behavior.