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.

Typo

Test against Django 1.8.6

Proper 'primary key' checking on to_fields.

Allow HTML to render when no filter_class is defined.

Request parsing when .POST accessed

docs - reverse needs kwargs keyword