Merge pull request openedx#114 from edx/efischer/django_upgrade

Prep for django 1.11

Merge pull request openedx#112 from edx/sstudent/upgrade-x

upgrade xblock

Merge pull request openedx#105 from edx/mattdrayer/update-xblock-refe…

…rence

mattdrayer/update-xblock-reference: Bump to 0.4.7

Merge pull request openedx#66 from edx/ned/upgrade-django-18

Upgrade to Django 1.8

quality fixes