Thanks David Nelson Adamec for the report and Tim Graham for the review.

When using a TransactionTestCase with serialized_rollback=True,
after creating the database and running its migrations (along with
emitting the post_migrate signal), the contents of the database
are serialized to _test_serialized_contents.

After the first test case, _fixture_teardown() would flush the
tables but then the post_migrate signal would be emitted and new
rows (with new PKs) would be created in the django_content_type
table. Then in any subsequent test cases in a suite,
_fixture_setup() attempts to deserialize the content of
 _test_serialized_contents, but these rows are identical to the
rows already in the database except for their PKs.  This causes an
IntegrityError due to the unique constraint in the
django_content_type table.

This change made it so that in the above scenario the post_migrate
signal is not emitted after flushing the tables, since it will be
repopulated during fixture_setup().

"Area man/woman" is confusing to people not familiar with the
conventions of American journalism (like me).

django-developers thread:
https://groups.google.com/d/msg/django-developers/11XvmVdx58w/sFrF0pL8LTgJ

Unused since efb0100e.

Thanks Anssi Kääriäinen for help.

Thanks Maxime Lorant for the report and Tim Graham for suggesting
the improved comment.

jQuery cookie is no longer maintained in favor of the JavaScript
cookie library. This also removes the jQuery dependency.

The test is a regression for refs #4740 to show that the original
fix of GEOSIndexError is no longer needed.

Thanks Florian Apolloner and Carl Meyer for review.

This is a security fix.

Thanks Carl Meyer for the report and Tim Graham for the review.