Fixed gemboard bugs. Added monsters. Added functions to Dungeon.

Monsters now spawn in the middle of random rooms. Also fixed bugs on gem
board for stat updates. Those now work correctly with each color
corresponding to a swap gem. In addition, fixed bug so that only gems on
board will be swapped (no clickoutside errors).
Also added some functions to dungeon so I can get numRooms and center of
any given room.