Fix documentation; add Keycode.SPACE

Fixes issue #6. Some Keycodes were missing from the published documentation due to a sphinx configuration issue. Keycode.SPACE is added as an alias for Keycode.SPACEBAR.

1.0.0 @dhalbert rocks

Thanks to @dhalbert this library has been greatly improved. It now features a separate Keycode class along with improvements to the Mouse class.

Initial release for bundle

Contains basic HID related constants.