AI and paddle reflection updated

-Now the paddle reflects in a much nicer feeling way. There are no
longer three discreet zones, instead there is now a gradient across the
paddle.
-Difficulties are now a little more realistic
-AI has some randomization to it, not enough but that will have to be
worked on.
-As an additional feature to the AI reaction time should be added where
the ai cannot switch direction until x amount of milliseconds has passed
making it more human-like. Need to implement this.