MDL-18014 Atto: Autosave text every N seconds.
MDL-18014 Atto: Add notification support to Atto.
MDL-18014 Atto autosave: Change default autosave frequency to 60 seconds
MDL-18014 Atto autosave: Show warning when the server cannot be contacted for autosave.
MDL-18014 Atto autosave: Correct detection of autosaving error when session expired