Remove call to parent onRemove, was causing add/remove errors

Author: Peter Rushforth

src/mapml/layers/MapTileLayer.js

@@ -55,8 +55,8 @@ export var MapTileLayer = GridLayer.extend({
   onRemove: function (map) {
     // Clean up pending tiles
     this._pendingTiles = {};
+    // remove _container from the dom, but don't delete it
     DomUtil.remove(this._container);
-    GridLayer.prototype.onRemove.call(this, map);
   },
 
   _handleZoomChange: function () {