New StateController for NPC

Now the NPC will use StateController and SearchingState to collect word
gems. The NPC will "collect" the gems by making them deactivate using
NPC1ItemController. NPC1 moves much faster than cat player so we will
probably want to slow it down. We can also talk about combining our
current SearchingState and StateController. However if we create
ChasingState we may also want to use much of the same code inside
SearchingState.
Merge pull request #10 from galaxode/master

New StateController for NPC (and NPC1ItemController - bare minimum)