Added curve command, added the functions to the CourseDataManager class to enable assuming grades and curves but haven't implemented those commands yet. Next on the list is to do that, add disenroll, and unassign commands, and to add the fuctionality of having grading the assignments based on a curve. These should all be pretty easy because all the structure is in place now. Shouldn't be more than 100 lines to finish up that. I also need to format the grade output for assignments so they only print a few decimal places, yikes.