An exam can have more than one kinf of deadline ...

Hence, renamed the deadline column to disambiguate
Files renamed and edited to highlight that it is exams that are built - not worksheets
Some additional references to worksheet builder replaced with exam builder
Wrong modal shown as part of exb
 more references to wsb removed
Minor edit
Added a name? method for sake of consistency
[Work allocation]: First draft of changes to allow explicit specification ...

... by the teacher of how scans should be distributed amongst TAs ( if any )