Removed empty gis models.py

Refs #22645.
Fixed #23812 -- Changed django.utils.six.moves.xrange imports to range
Updated advice on six.moves.range/xrange; refs #23812.
Ammended release notes for Refs #23969

(this includes a forward-port of 9189ef438ef885446b20bf4c017d3cf53335ab08)
Removed obsolete code for running test_loaders.py.

Running this file as a standalone script doesn't work anyway.
Fixed #23992 -- Optimized reorder_suite functions using OrderedSet
Fixed timesince translations for Korean

Refs #23989.
Forward port of eb632bfba from stable/1.7.x.
Merge pull request #3730 from tchaumeny/test_suite_reorder

Fixed #23992 -- Optimized reorder_suite functions using OrderedSet
Fixed #23991 -- Apparently, Oracle doesn't need the decimal field converter

Thanks Josh Smeaton for review.
Changed internal storing of abstract and concrete managers to be in a single list.

This commit prepares the internal manager layout to be serialized by
migrations; refs #23822.
Fixed #23822 -- Added support for serializing model managers in migration

Thanks to Shai Berger, Loïc Bistuer, Simon Charette, Andrew Godwin,
Tim Graham, Carl Meyer, and others for their review and input.
Fixed #23884 -- Moved FlatPageSitemap into django.contrib.flatpages.
Moved an import in an auth test; refs #23925.

This keeps tests/__init__.py from importing other modules and may fix a problem
with test discovery revealed in formtools tests on Travis CI.
Refs #23947 -- Fixed admin_views test execution order dependency.
Corrected test assertion from refs #21403.
Refs #23947 -- Fixed queries test execution order dependency.

Specify an id to avoid conflict with objects created in setUpTestData.
Fixed #23987 -- Made SQLite SchemaEditor always use effective_default().
Fixed typos in docs/releases/1.7.2.txt.
Fixed #23405 -- Fixed makemigrations prompt when adding Text/CharField.

A default is no longer required.
Fixed reverse test execution for migration manager tests

Thanks to Tim Graham for reporting the issue; refs #23822