title: Catchable Fatal Error when logging with twitter in my symfony2 application
body: <p>i use FOSUserBundle and HWIOAuthBundle in my symfony2 application.
  I try to implement "sign in with twitter" and when i run my application in developpment mode i have this error : </p>
  
  <blockquote>
    <p>Catchable Fatal Error: Object of class
    HWI\Bundle\OAuthBundle\OAuth\Response\PathUserResponse could not be
    converted to string</p>
  </blockquote>
  
  <p>here the stack trace :
  in vendor/symfony/symfony/src/Symfony/Component/Security/Http/Firewall/AbstractAuthenticationListener.php at line 216 </p>
  
  <pre><code> private function onSuccess(Request $request, TokenInterface $token)
      {
          if (null !== $this-&gt;logger) {
              $this-&gt;logger-&gt;info(sprintf('User "%s" has been authenticated successfully', $token-&gt;getUsername()));
          }
          $this-&gt;securityContext-&gt;setToken($token);
  </code></pre>