Create Quarter.java, QuarterTest.java, and add initialization test case
Add test case for invalid initialization
Add test cases for removing categories from a course
Add code for removing categories from a course
Add test code for removing items from a category
Add code for removing items from a category
Add test code for editing the GPA, lower limit, upper limit of rubric
Add code for editing the GPA, lower limit, upper limit of rubric
Add test code for editing the letter grade for rubric
Add code for editing the letter grade for rubric
Add code for removing a letter grade from rubric
Add code for removing a letter grade from rubric
Modify test cases to get 100% code coverage
Add test case for loading and saving rubrics
Add code for loading and saving rubrics
Add config.txt to the project