Displays a menu of choices (add volunteers, full time employees, or hourly employees)

The Assignment 5 class displays a menu of choices // (add volunteers, full time employees, or hourly employees, // compute their pay, search a member, list members, // quit, display menu) to a user. // Then it performs the chosen task. It will keep asking a user to // enter the next choice until the choice of 'Q' (Quit) is // entered