title: Assign classes for different tags in select2 multiselect
body: <p>Any ideas how I can pass a class to a jQuery select2 multiselect so I can style tags accordingly?</p>
  
  <p>I have the following HTML:</p>
  
  <pre><code>&lt;select data-placeholder="..." class="chosen-select" multiple style="width:100%;" tabindex="4"&gt;
        &lt;option value=""&gt;&lt;/option&gt;
        &lt;option value="user1"&gt;John Smith&lt;/option&gt;
        &lt;option value="user2"&gt;Richard Branson&lt;/option&gt;
        &lt;option value="user3" class="guest"&gt;Tim Cook&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>...and a simple js call:</p>
  
  <pre><code>$(".chosen-select").select2();
  </code></pre>
  
  <p>Note the "guest" class on the last option in the original HTML. I need to pass that class to the resulting tag generated in the select2 multiselect box so I can assign it a separate colour from the others.</p>
  
  <p>Hopefully someone can help shed some light on it!</p>