Practical problems with controller emulation:
	The keypad...  It would be nice if you could use the plugged-in keypad.
	But this requires quite extensive game patching

	Some games certainly have more complex controller read routines
		After all, at least Missile Command knows about analog controllers

	Nobody is going to remember all the eccentric mappings on their favorite controller

We need a good controller mapping screen:

	We should probably establish 'sequences' and 'auto-fire' rates
	Sequences let you hold down a button and cycle through weapons in Doom
	Or, hold down a button and cycle through special moves in your favorite fighter

	