Thanks Claude. Refs #20760.

Thanks to msaelices and d1ffuz0r for the initial patch and tests.

The code that tests to see which LIKE expressions to use now runs
using non-error-wrapped cursor, so cx_Oracle exceptions need to be caught
rather than Django DatabaseErrors.

Thanks Trac user ludo for report and initial patch.

Should be unneeded with Python 2.7 and up.
Added some unicode_literals along the way.

Thanks apollo13 for the report and review.

As some settings are copied from current user settings, we cannot
be sure the characters are pure ascii.

This was a shim for pre-Python 2.7 support.

Fixed #11195 -- Added CSS classes to the changelist cells to allow style customizations. Thanks to akaihola, Ramiro Morales and vdboor for their work on the patch.

(bug was already fixed in #19357)

Thanks CollinAnderson for the report.

It has been possible to use models of wrong type in related field
lookups. For example pigs__in=[a_duck] has worked. Changes to
ForeignObject broke that.

It might be a good idea to restrict the model types usable in lookups.
This should be done intentionally, not accidentally and without any
consideration for deprecation path.

Additionally this patch solves the orthogonal problem that specialized
`QuerySet` like `ValuesQuerySet` didn't inherit from the current `QuerySet`
type. This wasn't an issue until now because we didn't officially support
custom `QuerySet` but it became necessary with the introduction of this new
feature.

Thanks aaugustin, akaariai, carljm, charettes, mjtamlyn, shaib and timgraham
for the reviews.

Previously, the CachedLoaderTests were never run at all.

Thanks bmispelon for the report.

Thanks gcbirzan for the report.

Thanks simonb for the report.

any choices set by formfield_for_choice_field are still subject
to model validation of the model field's choices attribute

1. Automatically use tests/../django as the Django version.
2. If settings aren't provided through --settings or DJANGO_SETTINGS_MODULE)
   then use test_sqlite.

Fixed typo in Custom management commands documentation.