Refs #21271.

Thanks Tobias McNulty and Tim Graham for discussions and code review.
Thanks Andre Cruz the suggestion and initial patch.

Previously, when collecting static files, the files would receive permission
from FILE_UPLOAD_PERMISSIONS. Now, there's an option to give different
permission from uploaded files permission by subclassing any of the static
files storage classes and setting the file_permissions_mode parameter.

Thanks dblack at atlassian.com for the suggestion.

Thanks manfre for the report and Timo Graham for the review.

Added a refresh() before quit() in the selenium tests, since this
solves the problem of spurious test failures in some environments.

Previously there was a mixture of the two which resulted in inconsistent
casing.

Thanks jezdez for the suggestion.

Thanks Klas H for the report and claudep for the patch.

typo in 1.7 release notes

and how to prevent table-name truncation

Thanks russellm & timo for discussion, and timo for review.

Change strategy used to examine instrumented output to acommodate the
fact that on Windows, where the path separator is '\', repr() of Python
modules has changed in Python 3 to use escaped backslashes in the FS
path section (e.g.
'C:\\python3x\\Lib\\site-packages\\django\\contrib\\auth\\models.py')
without having to special-case based on platform.

Thanks joao at silvaneves.org for the report.

Thanks dan at dlo.me for the initial patch.

- Added __pow__ and __rpow__ to ExpressionNode
- Added oracle and mysql specific power expressions
- Added used-defined power function for sqlite

The old 'django_language' variable will still be read from in order
to migrate users. The backwards-compatability shim will be removed in
Django 1.8.

Thanks to jdunck for the report and stugots for the initial patch.

Thanks to flake8 path/to/file.py | awk -F ' ' '{ print $5 }' | sort | uniq

This shows itself with Python 3 under Windows where UTF-8 usually isn't
the default file I/O encoding and caused one failure and three errors
in our test suite under that platform setup.

When listing available management commands, only core commands are
listed if settings have any error. This commit adds a note in this
case so errors are not totally silently skipped.
Thanks Peter Davis for the report.

The typo could have consequences in exceptional cases, but I didn't
figure out a way to actually produce such a case, so not tests.

Report & patch by Michael Manfre.

The migration serializer now looks for a deconstruct method on any object.

This gives a 2x speed increase compared to the existing implementation.

Thanks to Steve Thomas for the initial patch and Tim Graham for finishing it.