Fix issue 74: OS X mouse exclusivity.
Fix issue 74: OS X mouse exclusivity.

niklaskorz/pyglet,niklaskorz/pyglet,adamlwgriffiths/Pyglet,seeminglee/pyglet64,niklaskorz/pyglet,adamlwgriffiths/Pyglet,seeminglee/pyglet64,adamlwgriffiths/Pyglet,seeminglee/pyglet64,adamlwgriffiths/Pyglet,niklaskorz/pyglet