Overall cleaned up the GUI code by moving any code dealing with a specif...

...ic panel into that panel's file. MainFrame is no longer doing the work of SimpleMode and SimpleMode is no longer doing the work of AddNewClass. Also, when adding a class, it now saves an XML file with the course information so that it will exist the next time the program is started. The table needs to be updated when a class is added still. Should refresh the table (redo the preload) after a course is added.