title: Zend 2 Navigation add <i> before label name
body: <p>I have the following navigation array, but now i want a  before my label. </p>
  
  <p>How and where can i add this?</p>
  
  <p>The output must be:</p>
  
  <pre><code>&lt;ul class="sidebar-nav"&gt;
      &lt;li class="active"&gt;
          &lt;a href="/admin/users"&gt;&lt;i class="gi gi-user sidebar-nav-icon"&gt;&lt;/i&gt; Users&lt;/a&gt;
      &lt;/li&gt;
  &lt;/ul&gt;
  </code></pre>
  
  <p>Array module config:</p>
  
  <pre><code> 'navigation' =&gt; array(
       'default' =&gt; array(
           array(
               'label' =&gt; 'Users',
               'route' =&gt; 'user_list',
               'pages' =&gt; array(
                   array(
                      'label' =&gt; 'add user',
                      'route' =&gt; 'user_add',
                   ),
               ),
           ),
  </code></pre>
  
  <p>Navigation :</p>
  
  <pre><code>echo $this-&gt;navigation('navigation')
      -&gt;setTranslator($this-&gt;plugin('translate')-&gt;getTranslator())
      -&gt;menu()
      -&gt;setUlClass('sidebar-nav')
      -&gt;setMaxDepth(0)
  </code></pre>