added preliminary refresh control implementation
moved photo fetching to separate thread; added activity indicator/network activity indicator during network activity
added refresh control to tag browser controller and activity indicator to photo view controller
added activity indicators to iPad photo views and hooked them up to the view controller code
removed the refresh control outlet since it needs to be set in code anyway
implemented the refresh control action to pull the Flickr photos and reload the table data; displays network activity indicator when fetching Flickr photos
added refresh control to tag browser controller
consolidated network activity indicator access to a single, thread-safe class so multiple threads handle the indicator correctly