Give teachers the ability to unhide assignment to individual students.

Where an assignment/quiz have been past due, it is very important for the teachers to hide it in some way to minimize cheating, etc. However, should the student want to do a make-up, at the moment, teachers are not capable of opening the assignment/quiz to selected students only. We can try reassigning it, BUT it will delete any previous answers that they have done already. It should be so that we can choose to reopen only for specific students on the same assigned activity.