Fixed #22338 -- Fixed a test dependent on dictionary key iteration order.
Ensure that a file is closed in the tests
Corrected many style guide violations that the newest version of flake8 catches
Added Python 3.4 to classifiers in setup.py.
Corrected an import in a model form docs example.
Fixed #22359 -- Changing M2M field to blank=True failed on sqlite.
Fixed #22319 -- Fixed migration external dependencies when there are internal dependencies.
Fixed typo in docstring.
Added 1.6.3 release note for refs #22250.
Fixed #21795 -- Made add_preserved_filters account for url prefixes.

Thanks to trac username honyczek for the report. Refs #6903.
Replaced urllib/urlparse imports with from django.utils.six.moves.
Fixed #22362 -- Improved AuthenticationMiddleware assertion message.

Thanks Keryn Knight.
Fixed #22360 -- Fixed two non-deterministic tests in Python 3.4.

The order of admin's changelist filters in the querystring relied on
dict ordering.
Added test to confirm #12583 resolution
Fixed #22327 -- Turned BaseEmailBackend into a context manager

Changed the BaseEmailBackend to allow usage as context manager to open
and close connections.
Added 1.6.3 release note for refs #22256.
Don't copy list for iteration.
Refactor. Stop using memory for list copies.
Merge pull request #2508 from tomwys/patch-1

Don't copy list for iteration.
Merge pull request #2509 from tomwys/patch-2

Refactor. Stop using memory for list copies.