If a NestedBoundField field has a value of `None` and is inside another NestedBoundField field, it will have its value converted to an empty string while the form of its enclosing field is being rendered. So, NestedBoundField fields with an empty string value must be handled the same way as NestedBoundField fields with a `None` value.

Fix for Incorrect regex in URLPathVersioning documentation #3638

Document how to turn pagination off

Make DRF compatible with multi template engine in Django 1.8

Update Django versions

doc: clarify that crispy-forms needs to be in INSTALLED_APPS

Fix typo in docstring for ReadOnlyField

Fix #3252 -- Use related_objects api for Django 1.9+

Documentation fix for list serializers.

Sort response headers in api renderer 

update docs about detail page link for AdminRenderer

Fix template.render deprecation warnings for Django 1.9

ListField does not enforce that input is a list

Test against Django 1.9rc1

Removing references to get_paginate_by() as it no longer exists.

Relation fields no to_fields attribute attribute break serializer

Fix regression causing raw data form to not display

Fix module name with Python 3.5 (#3534)

Don't specify unnecessary basepython

tox automatically includes basepython definitions for all the common
python versions, and will recognize it in factors of envs in the
envlist.