Gravity Control, "World Rotation" and Camera Functionality

added rotating camera and gravity with upright player and controls, added reference to player to physicist game screen, remapped control keys for WASD movement and <- -> camera control, integrated camera into game screen with camera functions in the game screen and calling of these functions from the player, who updates the world rotation in the update step.

ISSUE:  the player's body's shape does not rotate with the sprite, so collisions are not correct.  I feel that this issue cannot be resolved over the summer without collaboration, so I would like to merge.