Joypad as keyboard

[stevesims]

Allowing joypad buttons to act, effectively, as if they were keyboard buttons could allow for easier integration of joysticks into games and other programs.

An option to automatically map joypad 1's up/down/left/right to arrow keys, the A button to be "return" and B button as "space" could be very useful.

This could allow, for example, a file browser program like MC to allow the user to interact with a joypad.

See also #107 and #106