Cleanly fail when the user fails to provide initialize or logic-step.
renames <js-state> -> <input-state> and related functions.
adds license comment to top of init-logic.scm.
adds always_step to step every time the input is polled, regardless if
it changed or not
replaces oldjs with scm_old_input_state to be more generic.
Renames process_joystick to process_logic.
piston state.
I don't even know any more...