title: issue with removing polyline google map v2 android
body: <p>I am adding a polyline option simply as in google developer's website. </p>
  
  <pre><code>PolylineOptions rectOptions = new PolylineOptions()
          .add(new LatLng(37.35, -122.0))
          .add(new LatLng(37.45, -122.0))  // North of the previous point, but at the same longitude
          .add(new LatLng(37.45, -122.2))  // Same latitude, and 30km to the west
          .add(new LatLng(37.35, -122.2))  // Same longitude, and 16km to the south
          .add(new LatLng(37.35, -122.0)); // Closes the polyline.
  
  // Get back the mutable Polyline
  Polyline polyline = myMap.addPolyline(rectOptions);
  </code></pre>
  
  <p>I want to remove it. but there is no <code>rectOptions.remove()</code> 
  I did update google play services from my sdk as mentioned in <a href="https://stackoverflow.com/questions/15139271/google-maps-android-api-v2-how-to-remove-polylines-from-the-map">Google Maps Android API v2, how to remove Polylines from the map?</a>
  But still I dont have it. Should I do something more after just updating it from SDK manager? I really need to remove it and not make it invisible to save memory cause I will show a path of lots of points and for many times.</p>