Fixed Conveyor to be more like a subsystem as specified by Mr. Malins.  Also made Conveyor a parent class to be used by all subsystems operating with a conveyor belt.

created the subsystem Loader, child of Conveyor, for the subsystem responsible for loading the frisbees from the convey-ive system to the shooter
Minor clean up of constructor for Conveyor class, added get methods for the *Mode classes in Loader and Conveyor