***	Move game logic into a script so we can have "variations".
*	Then an in-game menu to choose which game:
		Rock Dodger
		Free-form/Practice
		Crazy Taxi
*	Add networking for multiplayer games:
		Tag
		Deathmatch

**	Switch all ray-traced graphics (only big green messages left)
*	Then we can run at the native screen size

*	fix rock generation code so they are never created overlapping

*	Deltas on high score display?


Comments from HappyPenguin (and solution ideas by Josh)

**	Why can't you go left?  Blast wave.  Fire/explosion graphics?

DONE 2006-03-25
***	Too hard.  Add easy setting (press 'e' to start easy game).
**	What do you do at game over?  Need an explanatory message.
DONE 2006-03-24
**	Multiple deaths is a problem: sqrt(ship speed).
