title: Sonata admin, editable field with choice
body: <p>I'm using sonata admin and there is an option <code>'editable' =&gt; true</code> for edit directly inline datas on the list view.</p>
  
  <p>If my field is a text, it's ok, i can click, edit the text and save directly on the table.</p>
  
  <p>But i don't want an input <code>type="text"</code> when i click on the field, but a list, i'm trying something like : </p>
  
  <pre><code>-&gt;add('etat', null, array('editable' =&gt; true), 'choice', array(
                  'choices'   =&gt; array(
                      'Brut'   =&gt; 'Brut',
                      'NRP' =&gt; 'NRP',
                  )
              ))
  </code></pre>
  
  <p>But no effetc.. is this possible ?</p>