+ Added Feed Configuration activity.
Fixed hiding of progress in the actionbar on FeedList screen, when no Feeds are loaded.

The loading finished before the menu could be initialized, so the menu item wasn't there yet to have the progress action view removed.
Empty text for the Feed Configuration screen, when there're no feeds in the database.
Moved the feed fetching and parsing logic to a FeedSyncService.

The service can later be used for automatic fetching every couple of hours.