No way to view deltas/changes in student work

[s-edwards]

While an instructor can view a student's work, and through the history tab in the dock, view past versions of that work, there is no easy way for an instructor (or student) to see what "changed" between two versions (say, the currently selected version and some other version shown in the history). Providing the equivalent of a git diff between versions would be a nice enhancement to address this.