Resource Dispenser Startup and Shutdown

When a resource dispenser's DLL loads, it must register itself immediately (before user calls) with DispMan. The resource dispenser first calls the GetDispenserManager function and then calls the IDispenserManager::RegisterDispenser method, passing the IDispenserDriver pointer that the resource dispenser implements. This call returns a reference to IHolder. To shut down, a resource dispenser calls IHolder::Close.