Django 1.10 support

[zoidyzoidzoid]

PR for tracking support for Django 1.10

• django.conf.urls.pattern has been removed
• checking namespace/app_name patterns stuff still works (I blindly deleted lines that might
  need to come back)
• django rest framework issue:

Unhandled exception in thread started by <function check_errors.<locals>.wrapper at 0x102796158>
  File "/src/git/ctpug/wafer/wafer/users/urls.py", line 14, in <module>
    url(r'^api/', include(router.urls)),
  File "/src/git/ctpug/wafer/virtualenv/lib/python3.5/site-packages/rest_framework/routers.py", line 79, in urls
    self._urls = self.get_urls()
  File "/src/git/ctpug/wafer/virtualenv/lib/python3.5/site-packages/rest_framework/routers.py", line 321, in get_urls
    urls = format_suffix_patterns(urls)
  File "/src/git/ctpug/wafer/virtualenv/lib/python3.5/site-packages/rest_framework/urlpatterns.py", line 64, in format_suffix_patterns
    return apply_suffix_patterns(urlpatterns, suffix_pattern, suffix_required)
  File "/src/git/ctpug/wafer/virtualenv/lib/python3.5/site-packages/rest_framework/urlpatterns.py", line 27, in apply_suffix_patterns
    view = urlpattern._callback or urlpattern._callback_str
AttributeError: 'RegexURLPattern' object has no attribute '_callback'

[drnlm]

Django rest framework gained support for Django 1.10 with encode/django-rest-framework#4158 , but that hasn't made it into a release yet.

[drnlm]

Since we've dropped support for Django 1.7, and django-restframework has had a release supporting 1.10, we should resume looking at this.

[zoidyzoidzoid]

Found a new PR to subscribe to, which is blocking this one: zsiciarz/django-markitup#19

Though there is some tidying up I can still do for the namespacing stuff.

[drnlm]

We probably to explicitly test whether the DJANGO_VERSION string is pointing to master, rather than trying to come up with a pip command that handles both cases

Since Ubuntu won't have bash built with regex command, some hack along the lines of

if [ "${DJANGO_VERSION/master/" != "$DJANGO_VERSION" ]; then
   # Django master
   pip install $DJANGO_VERSION
else
  # Numeric version
   pip install 'Django=~'"$DJANGO_VERSION"
fi```

[drnlm]

👍

[hodgestar]

If we're going to have complicated things in $DJANGO, it should probably be quoted here.

[zoidyzoidzoid]

The one Travis run is trying to build CTPUG's django 1.10 branch instead of my fork's branch.