Deletes updateFrames method
Adds AddSemesterController
Removes tint color property
Adds new class Semester
Implements semester helper methods and adds tests
Adds semester compare method
Implements addSection in terms of semester struct
Reimplements addCourse in terms of Semester struct
Replaces private method implementation to get index by semester
Changes Schedule interface to use Semester struct
Implements schedule enumeration in terms of semester struct
Changes implementation of Schedule to use data in terms of semester