Add a grade field to the Grading Project Survey form.
This also takes care of validating and transforming the data into True(pass) or False(fail). GradingProjectSurveys are hereby working for developers.
Reviewed by: Lennard de Rijk
Benjamin Niemann <pink at odahoda dot de>: Main developer of Python target.
Clinton Roy <clinton.roy at gmail dot com>: AST templates and runtime.