Added Split Ball Power-Up via clone() method. Modified bounce methods to public status.
Added a background image for the game.
Added Split Ball Power-Up.
Added Bricks sorting in preparation for Falling Bricks Power-Up.
Added Split Ball Power-Up.
Added availablePowerUps array to allow Power-Up selection.
Implemented Comparable<Brick> to allow for sorting and Falling Bricks Power-Up.