make UI display properly for newer polymer version

Author: kzahel

polymer-ui/index.html

@@ -17,7 +17,7 @@
         <paper-icon-button id="help-icon" icon="help-outline"></paper-icon-button>
         <img src="../images/200ok-64.png" srcset="../images/200ok-128.png 2x" />
       </paper-toolbar>
-
+</paper-header-panel>
 
 
       <div class="content" style="margin-left:2em; margin-right:2em; margin-bottom:0.5em; margin-top:0.5em">
@@ -149,7 +149,7 @@ <h2>Help</h2>
 
       </paper-dialog>
       <!-- end dialog -->
-    </paper-header-panel>
+    <!--/paper-header-panel--><!-- for older polymer, it needs to end here instead -->
     <script src="index.js"></script>
 
   </body>