Revert to Django 1.11
Revert to Django 1.11

This also includes git references to modules that have outstanding PRs
to make them compatible with Django > 1.10.  My current plan is to get
tests passing on 1.11, and then attempt 2.x again.

wger-project/wger,wger-project/wger,rolandgeider/wger,petervanderdoes/wger,petervanderdoes/wger,rolandgeider/wger,petervanderdoes/wger,rolandgeider/wger,wger-project/wger,wger-project/wger,petervanderdoes/wger,rolandgeider/wger