Set the new layer.grid to a new Array object, rather than null, in Layer.Grid.clone(). Passes all tests. Fixes #203.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@1616 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/Grid.js

@@ -69,8 +69,8 @@ OpenLayers.Layer.Grid.prototype =
             obj.tileSize = this.tileSize.clone();
         }
         
-        // we do not want to copy reference to grid. that should stay at null
+        // we do not want to copy reference to grid, so we make a new array
-        obj.grid = null;
+        obj.grid = new Array();
 
         return obj;
     },