Added checkbox and changed wording

EV-531
Changed lines that were mispelled

EV-531
Added function to permRule to check if the supervisor sig. is viewable

EV-531
Added tests and a description for the new added function in permRule

EV-531
Changing coding style

EV-531
Removed unnecessary imports/variables.

EV-531
Function now accounts for status of ReviewDue, added test case

EV-531
Merge branch 'feature/EV-531-add-supervisor-signatur' into liferay6