Bug: The man doesn't come to rest when friction is on.  What's wrong here?
Why does 0.006 friction have such a large effect?  Is this correct?
[internal] Figure out the meaning of the magic grab number in EnergyConservationModel
Rescalable Energy vs Position graphs.
Have to push record to graph...
Record bug:
	Record, then live, then record resets to last record state.	
Add clipping to energy vs position plot.

Falls through the track at various times? (Wendy)
Add game-ish modes to sk8r application
	. 2-skater mode
	. Grab the apple?
	. Jump the buses?
Crashing skater?
Test 1024x768:
	Skater is tiny at 1024 x 768
Bug: When user drags track that skater is resting on, the skater doesn't move with it.
User-selectable skater/vehicle graphics.