Correctly reschedule already updated feeds

If we request to update a feed that was just updated, previously we would
zero out the next update time (thus forcing it into a loop of updates)
because the next update wasn't set. Now, set it normally so that it is
correctly in the future.
Run update feeds on dev server always
Slower
Default feed last viewed to created time
Disable updating for not viewed feeds
On old feed view, re-enable and update