Provide graders with access to solution code

[alexstaeding]

It is currently impossible to directly access solution code in a grader. This may be sensible in a situation where a comparison between a submission and the solution is necessary.

A workaround is to duplicate solution code into the grader section of the grader jar, but this is not a good solution.

Deliverables:

• Come up with a clean way of accessing solution classes, possibly via the RuntimeClassLoader