Forgive this commit message, there's a dog on my keyboard.  It works!
I'm sure there are still edge cases where it will segfault, and I haven't
tried it in a dungeon yet, but it works! Run it and find a spawner.  As soon
as something spawns, it will run over.  Currently, they stand on the same square
as you.

TODO:
-Change it so that overflowing arrays are taken care of by padding the surroundings
 with immovable tiles instead of changing the radius at which the player is detected
-Make enemies move next to you, but not on you
-Put in a delay for enemy movement?