title: determine if MKMapView was dragged/moved
body: <p>Is there a way to determine if a MKMapView was dragged around?</p>
  
  <p>I want to get the center location every time a user drags the map using <code>CLLocationCoordinate2D centre = [locationMap centerCoordinate];</code> but I'd need a delegate method or something that fires as soon as the user navigates around with the map.</p>
  
  <p>Thanks in advance</p>