#20432: Fix for GroupAdmin test
Fixed #20235 -- Use self.object_list if object_list not present in get_context_data kwargs.

This is so MultipleObjectMixin can be used in the same way as
SingleObjectMixin.
Fixed #13546 -- Easier handling of localize field options in ModelForm
Merge pull request #1083 from Markush2010/ticket20235

Fixes #20235 - MultipleObjectMixin requires object_list in kwargs
Merge pull request #1084 from erikr/master

Fixed #13546 -- Easier handling of localize field options in ModelForm
Fixed #20269 -- Adapted PostGIS template create script for CentOS/RHEL

Thanks Stephane Benchimol for the report and the initial script and
mfandreas for the patch.
Fixes #19919: get_language_from_request() disregards "en-us" and "en" languages
when matching Accept-Language
Fixed argument order for localized_fields to ensure backwards compatibility
Merge pull request #1100 from ambv/issue19919

Fixed #19919: get_language_from_request() disregards en-us and en
Merge pull request #1101 from erikr/master

Fixed argument order for localized_fields to ensure backwards compatibility
Fixed #9595 -- Allow non-expiring cache timeouts.

Also, streamline the use of 0 and None between cache backends.
Merge pull request #1088 from jacobb/upstream

#20432: Fix for GroupAdmin test
Fixed #18998 - Prevented session crash when auth backend removed

Removing a backend configured in AUTHENTICATION_BACKENDS should not
raise an exception for existing sessions, but should make already
logged-in users disconnect.
Thanks Bradley Ayers for the report.
Slightly reworked imports in contrib.auth.__init__
Added stripping of whitespace for SlugField and URLField
Merge pull request #1113 from denibertovic/master

Fixed #18761 -- Added whitespace stripping to URLField and SlugField.
Fixed #19436 -- Don't log warnings in ensure_csrf_cookie.
Moved IgnorePendingDeprecationWarningsMixin in django.test.utils.

This mixin is useful whenever deprecating a large part of Django.
Fixed #20444 -- Cookie-based sessions does not include a remote code execution-warning
Fixed #13285: populate_xheaders breaks caching