chore(demo): update to hammer on google cdn

Author: kara

src/index.html

@@ -24,8 +24,7 @@
   <script src="vendor/angular2/bundles/http.dev.js"></script>
   <script src="vendor/angular2/bundles/router.dev.js"></script>
 
-  <!-- TODO: Replace with updated Hammer version in Google CDN -->
-  <script src="https://cdnjs.cloudflare.com/ajax/libs/hammer.js/2.0.6/hammer.min.js"></script>
+  <script src="https://ajax.googleapis.com/ajax/libs/hammerjs/2.0.8/hammer.min.js"></script>
   <script>
     System.config({
       packages: {