Added support for tailored messages when autosave is rejected
Optionally, the AJAX call from autosave can be answered with a JSON structure containing a "feedback". If this is provided, this is presented to the user. The mechanism can be extended in the future to include some reason code, etc. for further automatic processing in JavaScript.
With this change, the inclass-exam-answer workflow will use this to comminicate the reasone for rejected autosave operations in situations, where the examtime is up.