code: function(evt) {
          evt.layer.events.on({
              tileloadstart: this.makeSameOrigin,
              tileloaded: this.onTileLoaded,
              scope: this
          });        
      }
docs: Method: addLayer
  Adds a layer to the control. Once added, tiles requested for this layer
  will be cached.
  
  Parameters:
  evt - {Object} Object with a layer property referencing an
  <OpenLayers.Layer> instance