Added a master bitmap to pull character sprites from. It's in assets/character/. I updated the client code to load all the sprites (one for each possible player) when the game state changes to playing (we should use a splash screen here before starting the game).

The ordering for the character states in the image is as follows:
LEFT_STILL, LEFT_WALK_1, LEFT_WALK_2, LEFT_JUMP, RIGHT_STILL, RIGHT_WALK_1, RIGHT_WALK_2, RIGHT_JUMP,