Enable 'make docs' to work with Django>=1.8

docs/source/conf.py

 # Specify settings module (which will be picked up from the sandbox)
 os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'settings_sphinx')
 
+import django
+django.setup()
+
 # -- General configuration -----------------------------------------------------
 
 # If your documentation needs a minimal Sphinx version, state it here.