Allow re-scheduling within the 24 hour pre-fetch period
Currently schedules are fetched up to 24 hours in advance. In case the details of a schedule (such as the playlist tracks) are changing this is correctly updated within the defined period of
fetching_frequency (defaults to 1 hour). But when some schedule's start or end time is changed or the schedule is replaced by a completely different one, this is not updated with the Engine's schedule database.
To make Engine capable of such scenario, it require's deleting schedules which don't match any remote schedule and then storing the new ones.