- Move touch-handling code for "regular" touch joystick into separate file
- Add new touch-handling code for "keypad" touch joystick. This is a somewhat complex state-machine to determine
which key to press depending on a full keypad rosette.
- Adds a callback to vm.c to hook into keyboard read callback. Allows us to immediately queue the next key if the
keypad touch joystick is long-pressed for either axis or button keys.
