Merge branch 'version-3.1-2489' of git://github.com/brandoncazander/django-rest-framework into brandoncazander-version-3.1-2489

Conflicts:
	rest_framework/serializers.py

Cleanup '.model' shortcut from code and docs

Update filtering.md

Updated links for django-guardian package.

 ManyRelatedField.get_value clearing field on partial update

Use the proper db_table argument when constructing meta

Reload api_settings when using Django's 'override_settings'

Clone the versioning_scheme when necessary. Fixes #2477

Release notes for 3.0.4

A PATCH to a serializer's non-related CharField was clearing an ancillary StringRelatedField(many=True) field.
The issue appears to be in the ManyRelatedField's get_value method, which was returning a [] instead of empty
when the request data was a MultiDict.

This fix mirrors code in fields.py, class Field, get_value, Ln. 272, which explicitly returns empty on a partial update.

Tests added to demonstrate the issue.