title: Get global form errors from the FormView in twig template
body: <p>For rendering form errors in a twig template, you just have to use the <code>form_errors</code> twig macro without difference if it is a global form error or a field error.</p>
  
  <p>But in my case, a global error is not rendered like a field error, so I can't use the <code>form_errors</code> twig macro for the two cases. I decide to use the macro for the field error &amp; I would like to get the global form errors from the <code>Symfony\Component\Form\FormView</code> object. The goal is to iterate the global errors in the twig template &amp; render them like I want.</p>
  
  <p>Actually, I don't find any ressources on the symfony2 documentation which can help me.</p>