Corrected GameStick mapping

- Correct mapping for GameStick Controller on GameStick. This was tested with a development firmware and I'm still confirming with the GameStick team if the gamepad mapping changed for the devel firmware.

- Set default (unknown) controller to xbox360 mapping: Unity Webplayer + XBox360 controller gave the incorrect mapping and I think this could be as good as any other default schema given the popularity of this controller.