title: Mapbox annotation layer rotation resets on map zoom or move
body: <p>I'm trying to customize the appearance of the layers of my annotations in mapbox.
  I want to rotate every annotation layer.</p>
  
  <pre><code>- (RMMapLayer *)mapView:(RMMapView *)mapView layerForAnnotation:(RMAnnotation *)annotation
  {
      if (annotation.isUserLocationAnnotation)
          return nil;
  
      RMMarker *marker;
      CGPoint xy = CGPointFromString(annotation.userInfo);
      marker = [[RMMarker alloc] initWithUIImage:[UIImage imageNamed:@"arrow.png"]];
      marker.transform = CATransform3DMakeRotation(atan2f(xy.x, xy.y) * 180 / M_PI,0,0,1);
  
      marker.canShowCallout = YES;
  
  return marker;
  }
  </code></pre>
  
  <p>It works the first time they load on the map. But when I move or zoom the map they reset back to their initial transform identity matrix.</p>
  
  <p>Any ideas how I could solve this ? Or is it a bug of mapbox ?</p>