Conduit style input

[mardy]

input: use joystick for moving, pointer for rotation

Implement a control style a la "The Conduit", where the pointer is used to rotate the camera, and the joystick is used for moving. This still needs some work (we probably want to show a small pointer on the Wii screen, because currently it's hard to know where exactly you are pointing at), but should give an idea. Having playing "The Conduit" for a while, this feels much more natural to me.

This depends on #17 in order to be tested on the PC.

Addresses issue #1.