Backend changes for game mechanics

-Added new counter for "Game" score which counts the number of level's
won by each player (best of 4 with plans of a sudden death level if
even)
-Added singleplayer and multiplayer skeleton code
-Fixed mechanics for ball and bat movement/control with accordance of
game level
-Cleaned up the random ball velocity code and put it into a method
-Added game level mechanics skeleton code for drawing objects onto the
screen