Remove click-to-explode, it breaks on mobile
Replace control scheme with direct keyboard mapping in world
Bugfix for winding test on incomplete polygons
Tie weapon firing to the game clock and keyboard toggles

No more slow-time spamfests. Also, using keyboard toggles instead of the
raw keydown events means it's possible to maneuver while firing.
Remove mention of click interface
Make ship turn just a tiny bit faster
Add touch controls for mobile.

For now it's easiest to use the primary ("mouse") touch and ignore any
subsequent/additional touches, which requires more bookkeeping. It's
playable enough, I think.
Tweak fire control timers a bit
Merge branch 'better-controls'