Update tutorial thumbnails and add missing tileLayer/attribution variables for examples.

_layouts/v2.html

@@ -46,6 +46,11 @@
 
 		CM_URL = 'http://{s}.tile.cloudmade.com/d4fc77ea4a63471cab2423e66626cbb6/{styleId}/256/{z}/{x}/{y}.png';
 
+    MB_ATTR = 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, ' +
+        '<a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, ' +
+        'Imagery © <a href="http://mapbox.com">Mapbox</a>';
+    MB_URL = 'http://{s}.tiles.mapbox.com/v3/{id}/{z}/{x}/{y}.png';
+
 		OSM_URL = 'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png';
 		OSM_ATTRIB = '&copy; <a href="http://openstreetmap.org/copyright">OpenStreetMap</a> contributors';
 	</script>