Don't use ol.Collection in examples

examples/stamen.js

@@ -1,4 +1,3 @@
-goog.require('ol.Collection');
 goog.require('ol.Coordinate');
 goog.require('ol.Map');
 goog.require('ol.RendererHints');
@@ -7,7 +6,7 @@ goog.require('ol.layer.TileLayer');
 goog.require('ol.source.Stamen');
 
 
-var layers = new ol.Collection([
+var layers = [
   new ol.layer.TileLayer({
     source: new ol.source.Stamen({
       layer: 'watercolor'
@@ -18,7 +17,7 @@ var layers = new ol.Collection([
       layer: 'terrain-labels'
     })
   })
-]);
+];
 var map = new ol.Map({
   layers: layers,
   renderers: ol.RendererHints.createFromQueryData(),