anchor.diff:  The prefix follows the field type (email, required, match, etc.) for the
   message.
   
  -==== CSRF Protection
  +=== CSRF Protection
   
   mangoo I/O allows you to retrieve an authenticity token for protection
   against https://de.wikipedia.org/wiki/Cross-Site-Request-Forgery[CSRF].
  
positive.code: create a key "success", "warning" or "error" in the flash class. Besides
  that, you can pass custom values to the flash class.
  
  ==== Flash in templates
  
  To access the flash values, simply call the appropriate key in your
  template.
  
negative.code: be used. The mangoo I/O framework will automatically determine and use
  the strongest key possible.
  
  == Flash
  
  Specially when working with forms it is useful to pass certain
  informations (e.g. error- or success messages) to the next request. To
  