Added isVisibilityOptionsChanged to avoid making ajax call when there are no changes made to visibility options and preview visibility button is pressed
Reduced number of global variables that used to store visibility option string from 3 variables down to 1 variable
Refactor visibility options tracking to form data tracking as the changes in giver/recipient option should be considered as well
Fixed improper line indentation
Refactor further to improve readability
Update improper line indentation
Merge branch 'master' into Issue2303
[2303] Should not update the visibility message if no change is made to the visibility options in InstructorFeedbackEditPage