title: Animating a UITableView's header and footer
body: <p>I'm struggling to animate the removal of a tableview's header/footer content with animation.  I believe I can call either removeFromSuperview on the header contents itself, or just assign the header to nil, but I don't know how to animate this.  A simple animation block doesn't do anything - how do I fade a view (a label in this case) in/out?</p>