title: Unable to change core-animated-pages with paper tabs
body: <p>I'm trying to hook <code>core-animated-pages</code> with <code>paper-tabs</code> in my polymer appliaction. Everyghing looks cool , but I have trouble with changing <code>core-animated-pages</code> when I click on <code>paper-tabs</code> button 
  I'm trying to use <a href="https://www.polymer-project.org/0.5/articles/spa.html" rel="nofollow">This polymer tutorial</a> , my version is very similar to tutorial so it should work. Unfortunately I can see only first <code>core-page</code> active or my URL is changing for <code>http://myapp/#one or #two</code></p>
  
  <p>My code below:</p>
  
  <pre><code> &lt;template id="templ" is="auto-binding"&gt;
              &lt;div layout horizontal flex&gt;
                  &lt;paper-tabs id="tabs" valueattr="hash"  selected="all" class="progress-tabs" self-end&gt;
                      &lt;template repeat="{{page in pages}}"&gt;
                          &lt;paper-tab&gt;{{page.name}}&lt;/paper-tab&gt;
                      &lt;/template&gt;
                  &lt;/paper-tabs&gt;
              &lt;/div&gt;
  
              &lt;div layout horizontal center-center fit&gt;
                  &lt;core-animated-pages valueattr="hash" selected="{{hash}}"
                                       transitions="slide-from-right"&gt;
                      &lt;template repeat="{{page in pages}}"&gt;
                          &lt;section hash="{{page.hash}}" layout vertical center-center&gt;
                              &lt;div&gt;{{page.name}}&lt;/div&gt;
                          &lt;/section&gt;
                      &lt;/template&gt;
                  &lt;/core-animated-pages&gt;
              &lt;/div&gt;
  
          &lt;/template&gt;
  </code></pre>
  
  <p>And script:</p>
  
  <pre><code>  &lt;script&gt;
      Polymer('progress-page', {
          ready: function () {
              var template = this.shadowRoot.getElementById("templ");
              template.pages = [
                  {name: 'Single', hash: 'one'},
                  {name: 'page', hash: 'two'}
              ];
          }}
      );
  &lt;/script&gt;
  </code></pre>