Feed update interval is decremented by a 10% if new entries are fetched during an update.

Also, dynamically added scheduled feed updates are marked as persistent, so that they survive a Resque reboot. This is a recent addition which is not too well stested; still, the statically scheduled FixSchedulesJob should take care of any problems and fix schedules as necessary.
The interval between scheduled feed updates is incremented by 10% if no new entries are fetched during a scheduled update.