Grading drivers should reflect changes in assignments

[Sardtok]

Either the assignment code should be locked down at some point, or the grading drivers should be updated to reflect changes in the assignment code. Otherwise pulling new commits will result in mismatches between grading driver code and assignment code.

I'm guessing people will use common sense during grading, but you never know with the first point in the rubric, which basically says no changes should be made to the files except filling in the TODOs.

One way to avoid problems with this is to not change comments, even if they might be giving away hints as to how to solve the exercises. There are of course other possible problem areas.

There's no real need to have two copies either (one for grading and one for assignments), as one could just clone the repository to two different directories, one for grading and one for doing assignments.