A lot of chnages spanning multiple files. Category menus redone so as to not risk them going off the edge of the screen. Students can now be removed. Exporter now exports ghost students. Students and ghost students are sorted by PsuedoName before being exported. A bug which caused the program to crash when opening a newly created course was fixed. I can't find any bugs, please look.
Clearing category and add new class text fields when initializing them, so that they don't have text from the previous time.
Changed name of window to GhostGrader.
Zach found two bugs. One was giving index out of bounds when removing an assignment. One wasn't removing a student from the student table immediately when removing a student. Both are fixed.
Assignments now display worth while editing them.
Merge pull request #87 from GarbageElitist/final_changes_for_brett

Changes spanning many files.