title: All possible model validation errors
body: <p>I have got a form with a bunch of fields and model validations.</p>
  
  <p>How can I return all possible validation errors that can be raised?</p>
  
  <p>I need it to write locales for all of them.</p>
  
  <p>I want to get a list like this:</p>
  
  <pre><code>password blank
  password too_short
  password confirmation
  login blank
  login invalid
  email blank
  email too_short
  email invalid
  </code></pre>
  
  <p>etc</p>