Important change: teacher's assessments of example submissions (now
known as "reference assessments") are now displayed to students after
they assess example submission.
Moving stuff from lib.php into static methods in localib.php. Removing
things from workshop core that were implemented in a subplugin. Dropping
stuff related to features not to be implemented in 2.0.
Initial sketches of random allocator. Refactoring of the rest of the
module here and there. Also, this commit removes trailing whitespace and
running empty lines.
