title: How set Custom Annotation markers ( animated rings around a point) on GMSMapView
body: <p>Using Google maps iOS SDK I have implemented a mapView
  in that i have created markers as follows</p>
  
  <pre><code>// Creates a marker in the center of the map.
  GMSMarker *marker = [[GMSMarker alloc] init];
  marker.position = CLLocationCoordinate2DMake(-33.86, 151.20);
  marker.title = @"Sydney";
  marker.snippet = @"Australia";
  
  marker.icon = [UIImage imageNamed:@"point1.png"]; 
  
  marker.map = mapView_;
  </code></pre>
  
  <p>But i need to Display <strong>animated images ie some sequence of images to display, animated rings around a point, instead of original GMSMarker</strong></p>
  
  <p>sequence of images are point1.png point2.png point3.png point4.png point5.png</p>
  
  <p>Can any one help me to achieve this</p>