title: Umlauts not beeing displayed properly in symfony2
body: <p>Im having the following problem.
  If I try to use this code</p>
  
  <pre><code>$form = $this-&gt;createFormBuilder()
          -&gt;add('code', 'integer', array(
              'attr' =&gt; array('class' =&gt; 'login-input')
          ))
          -&gt;add('einlösen', 'submit', array(
              'attr' =&gt; array('class' =&gt; 'login-submit')
          ))
          -&gt;getForm();
  </code></pre>
  
  <p>my browser doesnt show the ö in einlösen.
  If i remove the class attr it works.
  I thought this might be a css issue but the problem seems to be with symfony, since there
  is no matter what class I use the ö always gets mangled.</p>
  
  <p>Another thing I realized is that if I do a cache clear the ö is there but as soon as i press the button once and reload the page its not showing up properly again.</p>