Adding tiled WMS source

As shown in the example, this adds support for tiled WMS layers.

examples/wms.js

@@ -0,0 +1,33 @@
+goog.require('goog.debug.Console');
+goog.require('goog.debug.Logger');
+goog.require('goog.debug.Logger.Level');
+goog.require('ol.Collection');
+goog.require('ol.Coordinate');
+goog.require('ol.Map');
+goog.require('ol.source.MapQuestOpenAerial');
+goog.require('ol.source.TiledWMS');
+
+
+if (goog.DEBUG) {
+  goog.debug.Console.autoInstall();
+  goog.debug.Logger.getLogger('ol').setLevel(goog.debug.Logger.Level.INFO);
+}
+
+
+var layers = new ol.Collection([
+  new ol.layer.TileLayer({
+    source: new ol.source.MapQuestOpenAerial()
+  }),
+  new ol.layer.TileLayer({
+    source: new ol.source.TiledWMS({
+      url: 'http://demo.opengeo.org/geoserver/wms',
+      params: {'LAYERS': 'topp:states', 'TILED': true}
+    })
+  })
+]);
+var map = new ol.Map({
+  center: new ol.Coordinate(-10997148, 4569099),
+  layers: layers,
+  target: 'map',
+  zoom: 4
+});