dirname() is a slow function compared with __DIR__ and using
'/../'. Moodle has a large number of legacy files that are included
each time a page loads and is not able to use an autoloader as it is
functional code. This allows those required includes to perform as
best as possible in this situation.
This way we can use the function gradingform_controller::render_preview() to display a preview for students in different modules
without worrying on gradingform-specific options on whether to display description for students or not
Also allow advanced grading plugin to extend course module navigation, it is not necessary only definition previewing
Added option to rubric whether to show it to the students before submission and option to view description
Russell Smith