Fixed #21499 -- Added a paragraph to the docs.
Fixed test failure on Oracle

Failure was introduced with test in [19e5cd77f0536b778b00788e34d8199835143855]
Fixed #21507 -- Corrected default widget information for FileField
Fixed #21403: Corrected test code

A test for annotations incorrectly assumed that the first instance
(in the test) of a model using AutoField for PK will always get pk=1.
The test was changed to compare against actual instance id instead.
flake8 fix
Fixed #21509 -- Removed dead exception catching code.

Since Python 2.5, KeyboardInterrupt and SystemExit are not subclasses of
Exception, so explicitly reraising them before the “except Exception” clause
is not necessary anymore.
Fixed #21489 -- Make formsets directly importable from django.forms.
Fixed #20522 - Allowed use of partially validated object in ModelAdmin.add_view formset validation.

Updated ModelAdmin to use form.instance when passing parent model to
child inlines for add_view. There is effectively no change in the
change_view since the previously passed 'obj' is the same as form.instance.

Thanks to meshy for report, and EvilDMP and timo for review.
Fixed #21512 -- Added more complete information about Pillow and PIL in model_fields and model_forms tests.
Use str.isupper() to test if a string is uppercased.
Fixed #21355 -- try importing _imaging from PIL namespace first.
Fixed #21448 -- Fixed test client logout with cookie-based sessions

Thanks Gunnar Scherf for the report and the suggested patch.
Fixed a typo in the documentation
Replace use of dict.has_key with `key in dict`
Merge pull request #1985 from raphaa/21499

Fixed #21499 -- Migrations won't work if field signature changes
Fix squashed migration loading ordering issue
Change initial migration writing to work as docs suggest.

Application template now includes an empty migrations module, and
the autodetector will only make initial migrations for apps with
empty modules.
Add gis deconstruct() method (this does not make schema work)
PostGIS schema editor support
Field.deconstruct() howto docs