Simplify rescheduling a script.
We don't need reschedule_termly_polls().
We don't need reschedule_monthly_polls().
We don't need reschedule_weekly_polls().
We don't need to be able to reschedule termly or monthly scripts individually.
We don't need to explicitly reschedule weekly or midterm polls.
Delete unused methods.
Added a command for clearing all current progress.
Delete commands that don't make sense when scheduling is done via the settings.
Update dates in unit tests to avoid unfortunate interrelation with 2013 holidays.