title: Glyphicon not displaying in Prestashop 1.6
body: <p>I am working on a prestashop module and I am trying to use a Boostrap glyphicon as a button in my template, but it does not work and I can not figure out why.</p>
  
  <pre><code>&lt;td&gt;
      &lt;button type="button" class="btn btn-default btn-lg"&gt;
          &lt;span class="glyphicon glyphicon-cloud-download"&gt;&lt;/span&gt;
      &lt;/button&gt;
  &lt;/td&gt;
  </code></pre>
  
  <p>My column stays empty, prestashop documentation shows this example but it it does not work either</p>
  
  <pre><code>&lt;div class="form-group has-warning"&gt;
      &lt;label class="control-label" for="input1"&gt;Label with warning&lt;/label&gt;
      &lt;input type="text" class="form-control" id="input1"&gt;
      &lt;span class="glyphicon glyphicon-warning-sign form-control-feedback"&gt;&lt;/span&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Is it something to add to prestashop ? Did I miss something ?</p>