Use prefetch to solve `Wird beim laden des Forms aktuell der 'value' als 'key' gesetzt, damit der User sieht was beim letzten Speichern gewaehlt ist.Damit ist dann der 'Key' verloren.`

 * use anonymous functions for ajax error displays
 * expect response from server to file upload to have `status` and `message` attributes
 * replaced occurrences of `QfqNS` by `n` in order to support different namespace names.

QfqForm.js: Form refresh is now known as form update. Form updates receive more elaborate response from server.