Feature Request: "Select all" on grading page

[hschnurbusch]

To allow students to register for another time slot it is necessary to grade the slot. One can also grade several slots at once. Nevertheless one has to check the "Attended" and "Allow reappointment" option for every single slot on the page. It would be less time consuming if there was a "Select all" option on top of the page as can be found in the Download Center plugin for example.