When refreshing a feed via Ajax, correctly prepend new entries in the list even if the list was empty (the previous method failed in this case). Correctly handle the case in which the feed server returns a 304-not modified response.

Also, minor change in styles: ensure that the cursor becomes a hand/pointer when hovering over a link, for all links. For some reason the cursor was becoming a text-select tool in this case, which looked ugly.
Fix Feed controller unit test. Also added a new example to that unit test.
Ensure that no actual HTTP calls to feed servers are done during acceptance testing.