Displays the date, time, and username of the most recent save and publish

@cahrens @andy-armstrong 
I think it would be a better test if the fake response included edited_on and edited_by too (so it is clear that it is ignored if has_changes is False).

So when has_changes = false, we say in 2 places what the last published date was? I guess I didn't realize the text in the "publish control box" changed from draft saved to last published.