title: $state.go and nav direction
body: <p>I have a ui-sref link.</p>
  
  <pre><code>&lt;a ui-sref="tab.search-results(backTo)" nav-direction="back" class="button no-margin-top bold button-full button-stable"&gt;
    &lt;span class="assertive"&gt;BACK&lt;/span&gt;
  &lt;/a&gt;
  </code></pre>
  
  <p>I'm using <code>nav-direction</code> to have the transition go back. How do I do this with <code>$state.go()</code>?</p>
  
  <pre><code>&lt;a ng-click="parts.goBack()" class="button no-margin-top bold button-full button-stable"&gt;
    &lt;span class="assertive"&gt;BACK&lt;/span&gt;
  &lt;/a&gt;
  </code></pre>
  
  <p>I don't see this option anywhere.</p>
  
  <pre><code>function goBack( ) {
    // How do I go back via nav direction?
    $state.go('tab.search-results');
  }
  </code></pre>