comments on how to reimplement question values used
fixes #19, much cleaner implementation of question limits by tallying question choices whenever needed
removes old question_values_used code. Very ugly. No more fiddling with stupid unreliable hooks.
comments out simultaneous bug fix in preparation for fix #22
fixes #22, reimplements simultaneous workshop bug fix. Much cleaner and reuses get_question_choices_tally
merging reimplement with master