wrong char in rst questionare id will break aplus.json generation #124
Description
A course has a questionare definition in rst-format: .. questionare:: t1_4.7 A8 rst->html generation goes ok, but when course config url (aplus.json) is referenced in mooc-grader it will throw exception and there is 500 http error (whole course config is broken).
Changing the id to questionare:: t1_4_7 A8 fixes the problem, so the dot seems to be the triggering char.
Tested against mooc-grader v1.9