A teacher can change the order in which assignment submissions are listed

This test requires an assignment with several submissions.

1. Log in as a teacher, access the assignment and follow the 'View all submissions' link.
2. Try sorting the submissions by first name by clicking the 'First name' heading.
3. Click the 'First name' heading again and check that the submissions are now sorted in the reverse order.
4. Try hiding one of the columns by clicking the hide icon next to a particular column heading.
5. Log out and log in again making sure the sort order is retained and column is still hidden.
6. Click 'Reset table preferences'
7. Ensure sort order is default and all columns are visible.
8. Log out and log in back, ensure default sort order is retained and all columns are visible.