Fix for issue 523.  Numeric keypad constants in docs don't match key.py.
Fix for issue 523.  Numeric keypad constants in docs don't match key.py.

niklaskorz/pyglet,adamlwgriffiths/Pyglet,niklaskorz/pyglet,adamlwgriffiths/Pyglet,adamlwgriffiths/Pyglet,niklaskorz/pyglet,adamlwgriffiths/Pyglet,niklaskorz/pyglet