Gamepad support

Thanks to Justin Arnold who added gamepad support in RPG in a Box, the game can now be played with a Xbox controller, and probably any other controller with a similar control scheme. It's a rather different experience compared to clicking with the mouse, with a more direct feel, but it may help immersion in another way. Since you're more active, it can feel a bit like a slow-motion racing game, or something along these lines.

As usual, feedback is wecome :)