removed nanoTime and Hashtable, to make code more compatible with GWT backend; started refactoring for next major change, which is using the Level interface for all screens
renamed PhysicsSprite to Actor
started the Store object, and did a bit more refactoring
made a note about a TODO
splash screen is now a physics screen.  this actually saved a ton of code
almost done with conversion of chooser to physics-based level
finished cleaning up configuration stuff
removed another extraneous config file
moved some utility codes around
a bit more refactoring, to change how we do configuration
a bit more cleanup
last bit of cleanup for this round of refactoring