Add scope view for GradingSurveyGroup and set access checks. The access checks are now properly set for create, edit and show. To facilitate the scope view the access check have an extra check built in to ensure that a scope is actually present before cheking for an existing Program.

Benjamin Niemann <pink at odahoda dot de>: Main developer of Python target.
Clinton Roy <clinton.roy at gmail dot com>: AST templates and runtime.