Complete rewrite of feed update schedule.
Use average stories per month in calc.
Correcting for premiums being counted twice.
Adding metric for last story date, used to calculate next scheduled update.
Merge branch 'master' into schedule

* master:
  Fixing ulimit on new machines. Upgrading celery.
Merge branch 'schedule'

* schedule:
  Adding metric for last story date, used to calculate next scheduled update.
  Correcting for premiums being counted twice.
  Use average stories per month in calc.
  Complete rewrite of feed update schedule.