[WIP] NPC Redux

This merges the active NPCs and the old NPCs into one class. Commands can be run via talking to NPCs. All NPCs now have a menu, so other information from the NPC can be added.
Still needs to be done:
- Check all NPCs function correctly

Side note: I am thinking of making it so that the bbox width and height default to that of the image width and height if not supplied, thoughts?