title: Check if user finished sliding on a continuous UISlider?
body: <p>In my app, I have a couple of UISlider instances to change various values. The values are displayed right next to the slider, as well as rendered in a 3d space in another visible part of the app.</p>
  
  <p>The 3d part includes some rather heavy calculations, and right now it doesn't seem possible to update it live as the slider changes. That would imply that I'd have to set the slider's <code>continuous</code> property to <code>NO</code>, therefore only getting updates when the slider has finished changing. </p>
  
  <p>I'd prefer to have the <em>displayed</em> value update live, however. Is there a way to have a slider that is continuous (so I can update my value-label in real time) and still sends some kind of message once the user has finished interacting with it? My gut feeling right now is to subclass UISlider and override the <code>touchesEnded:</code> method. Is that feasible?</p>