Camera

Camera clamps based on a border rectangle that is passed in. This border rectangle should have a width that is the same as screen size for the clamping to work properly. Also, there is a new SLACK variable that sets the amount of wiggle room that the camera has, ie the camera will ignore movement if it is less than the SLACK variable. (If this is a problem, we could always set it to 0 and then it would behave as if it doesn't exist)