helper functionality to correct a user's entire submission. + tests.
fixing flake8 issues
rolling back my changes. i pushed this too quickly, not considering multiple answer questions.
* bug fix for Question.user_responses. Exception thrown if no Submissions exist
Django 1.6 compatibility: django.conf.urls.defaults removed in favor of django.conf.url
ignoring flake8 W402 error that results from branched import in urls.py
1.6.4