[WIP] Trying to get linux joystick mappings to work?

The problem is that the joystick lists the dpad as an axis, with a hat.
The virtual gamepad uses buttons rather than axes for the dpad, so I'm
not sure how to set up that mapping. Everything else maps fine.
WOO! Got the dpad working
Merge branch 'joystick_mapping' into megaman_controls_2
Moved state update code into state machine
Wall Jump take 2

- Added a "sense" bubble so that megaman can detect nearby walls.
- Any time megaman is near a wall, he can kick off of it into a
jump.
- Megaman can cling to walls and slide down them.
Added blast flicker
[WIP] Megaman death explosion

- Megaman is removed from the screen after releasing rings of energy.
- full of constants at the moment
Removed constants

Probably the destroy module can be abstracted so that each player
can have their own color etc...
Added AIR DASH but not heavily tested
Added a module!
Added the highway_arena!
Merge pull request #10 from variousauthors/megaman_controls_2

Megaman controls 2