-Added bounding walls around perimeter of screen to contain bouncing balls.
-Added gravity toggle option instead of clearing screen on button press.
-Consolidated touch events to use common function call for updating FingerPoints array.
-Added freeze/unFreeze function to FingerPoints to prevent box2D physics motion while dragging until touchUp is called.
-Added text to screen indicating number of simultaneous touch points and gravity indicator.
-Added placeholder Pokeball graphic in leiu of drawn colored ball.
-Added ability to interpolate last 2 finger positions to give balls initial velocity on touchUp.
-Modified PPM() helper function to more descriptive PixelsToMeters(), and added secondary MetersToPixels() helper function.