Simplified implementation of is_due.
Simplified implementation of is_due.

There is no reason anymore to call out to _check_hour_minute anymore, since the
due calculation is now so trivial.

ask/celery,WoLpH/celery,cbrepo/celery,mitsuhiko/celery,ask/celery,WoLpH/celery,cbrepo/celery,mitsuhiko/celery,frac/celery,frac/celery