Changes

* The position values aren't are not reset after reading.* The position values do not change if the mouse doesn't move in that is not moving * Position values wrap around e.g. when moving left with movement speed of 1, 0 wraps around to ff (0-1 -> ff)and when moving right with movement speed of 1, ff wraps around to 0 (ff+1->0) * To calculated the distance moved since last read subtract the new value read from the previous value read and AND with ff. The value is the amount of movement.