Added more functionality to the simulator, requiring a few changes in the supporting classes:

	Started converting comments in simulator to functional/compiling code.
	Added comparison operator for ActionRecord.
	Added Agent destructor -- agent is now responsible for freeing the UserModel it owns.
		** Agent will likely also be responsible for initializing the UserModel, but this isn't implemented yet.
	Changed available_skills to set<Primitive*> from vector<Primitive*>