fixing a small bug with regexes behaving odd with pipes in fillin questions
adding a migration to add sort_order to responses, can't rely on the db to insert them in the order we want
making sure tests won't fail with an | fillin in the beginning
fixing  bug where an error would come up if you're submitting a quiz with a question that hasn't been answered
adding some validation to the Response model
merging with master
adding checking to make sure answers got put in the right order
added SORT_ORDER for fillins when submitting them to make sure they're in the right order -- added defaultScope to make sure that's taken into account when gets are gotten
Merge pull request #142 from Harvard-ATG/feature-137

Feature 137 -- fixes #137