Small fixes: Set unread count to 0 when marking all as read via action button. Add URL to log message when there was an error obtaining the feed.
Move more functionality into update_feed(). Add a force parameter to skip those checks.
If the feed itself has an updated date, use it. Also, improved logging.
Wrap all date handlers in try-catch. Skip feeds with invalid dates, e.g. translated. We can't handle and don't tolerate that.