changed label for an error message
Bugfix: back button wasn't working after downloading a file
Merge pull request #508 from cbartol/ticket/rt#416817-#416259

Changed the error message when attributing a final work to a student that already has one.
related to #500.
Also corrected a combobox that has a list of teacher's department, in the finding person menu (messaging portal).
closes #507
Merge pull request #510 from cbartol/ticket/rt#416925

Fix the unwanted behavior of the back button.
Instead of a back button, now is back link.
closes #509