Always disable the PWM after each command sent. Automatically trim
the command duration so the PWM disable doesn't increase the total
pulse time (when the duration is 200ms or greater).
Track the ideal command end time separately from the pwm transmit time
and only delay toolhead moves to this ideal time.
Update verify_state() to automatically schedule the check using the
time of the last sent command.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>