Fixed #8590: Confirmation added when answers are changed.
Fix for #8538: Abstention is shown on all questions
Fixed #8538: Enabled abstention answers for yesno and abcd
Fixed #8566: Sessions visited as student get their own icons
Fixed #8388: "delete all" button is hidden when no q's are present
Fixed #8563: Display total answers for students
Fixed #8558: Fixed displaying the wrong message
Fixed missing internationalisation of 'yesno' question answers (Task
#8605)
Fixed #6620: Use new server API to open/close questions