add test to gui constraint
add duplicate constraints check and error popup
Fix viewing invalid schedules.
add bool value is_mandatory to create constraint function
View schedules in a graphical way.
added tests to get priority value in gui constraint
add mandatory code to course constraint functions
add mandatory option to instructor constraints
fix mandatory priority display in added constraints window
Merge branch 'constraintCRUD' of https://github.com/donnell74/CSC-450-Scheduler into constraintCRUD
add before/after same time conflict check
add check for different sections of same courses not at same time
remove unnecessary comments
Remove room number, building, and day from view schedule output. And increase view schedule window size.
Merge branch 'constraintCRUD' of https://github.com/donnell74/CSC-450-Scheduler into constraintCRUD
added selectable constraints view
added delete all constraints in the gui
fixed bug: number of arguments
added delete selected constraints
fixed delete constraints