. Bug: When user drags track that skater is resting on, the skater doesn't move with it.
. Bug: The ground can't be driven on (only bounced off).
. Bug: A bounce entails a loss of energy (which I didn't intend).
. Fix Minor bug (but one which prevents foreign launch) of Schrodinger.
. Make object mass switchable.
. Change skaters/vehicles graphics.
. Add game-ish modes to sk8r application
	. 2-skater mode
	. Grab the apple?
. Add coefficient of restitution?