title: Check server response after a iron-form submit
body: <p>I am submitting a form using iron-form. However, when the server responds, I want to see what the response is so that I can:</p>
  
  <ul>
  <li>Either close the form (if everything was OK)</li>
  <li>Or highlight the "broken" fields (if the response was an error)</li>
  </ul>
  
  <p>I realise I can easily listen to <code>iron-form-error</code> to see if there were any problems. The error comes back as Json, where I have key/value where the key is the field name, and the value is the error message.</p>
  
  <p>In case the response was indeed an error, do I have to go through the response manually? Or is there a shorthand version to display the error messages automagically?</p>
  
  <p>Thank you!</p>