Also added tests for get_model.

Following the app-loading refactor, these objects must live outside of
django.contrib.sites.models because they must be available without
importing the django.contrib.sites.models module when
django.contrib.sites isn't installed.

Refs #21680. Thanks Carl and Loic for reporting this issue.

Thanks Aymeric for the suggestion.

Also document the conditions under which a namespace package may or may not be
a Django app, and raise a clearer error message in those cases where it may not
be.

Thanks Aymeric for review and consultation.

Thanks Sephi for the report.

Clarified that queries in autocommit mode are committed immediately
only if a transaction has not already been started. Added to the
main transaction docs that Django's TestCase class implicitly wraps
its tests in transactions.

Added ticket #14007 contributors to AUTHORS

BooleanFields are stored as TINYINT(1) on MySQL.

Fixed #21867 -- Removed AppStaticStorage; app paths are now AppConfig's job.

Thanks Russell for the report, Marc for the initial patch, Carl for the
final review, and everyone who contributed to the design discussion.

Thanks Aymeric for design discussion.

AppStaticStorage only provided one thing over FileSystemStorage, which was
taking an app name (import path) and translating it into a filesystem
path. This is now something that should be done via app_config.path instead,
leaving AppStaticStorage with no reason for existence. It should be safe to
remove, as it was undocumented internal API.

There was some kind of feature in the AppDirectoriesFinder code related to a
"prefix" attribute on the storage class used by AppDirectoriesFinder. Since
this feature was undocumented, untested, and of unclear purpose, I removed it
as well.

During the admin check for list_editable _check_list_editable_item
should return an empty list if all checks pass. Additionally the
Testcase test_readonly_and_editable was changed to test what the
name implies instead of duplicating the logic of test_readonly.

Thanks tragiclifestories for the report.

Maths is hard.

We fork at beta. This branch will be recreated when the first beta is created.
It has been merged in to maintain the version number bump and tag.

We should branch after the first beta.

We did this for 1.6 and it was very effective. 95%+ of fixes which merge
during the alpha are backported, as the policy is "all but really major
features". It's easier to just not merge any really major features.
After beta, we have feature freeze so we need to backport bugs to stable
but not features, so then the branch makes sense.

Fixes #21864: Close string in example of custom lookups doc page.

Thanks to Chris Barna for the report.

Thanks marktranchant.

We did this for 1.6 and it was very effective. 95%+ of fixes which merge
during the alpha are backported, as the policy is "all but really major
features". It's easier to just not merge any really major features.
After beta, we have feature freeze so we need to backport bugs to stable
but not features, so then the branch makes sense.

This is consistent with Python's official documentation
and it's a sphinx recommendation too[1].

[1] http://sphinx-doc.org/markup/desc.html#dir-method

Refs #21855.

Thanks Giggaflop and Jennifer Casavantes.