Background speed, game loop

I didn't want to wait till I had my surface before I did something
meaningful.  However, it happens that this code is a lot less recent
than I'd even assumed.  This commit makes a breaking change which
prevents page load.  I disconnected input from keypress dispatch by
removing keyboard state.  The next step is to cause keypress to dispatch
directly rather than event listening.  (a) it's faster.  (b) it's much
easier to understand (c) it first into the model which does timing, and
causes indecision to pass time.

This also allows for acceleration of background animation, so that while
passing time, the background can speed up.  Maybe it should also allow
for background freezing for flight mode?  It (sort of) allows that --
but neither functionality's called yet