Fixed documentation of disable_constraint_checking

The docstring and base implementation of disable_constraint_checking do not indicate that a return value is expected for proper behavior.
Fixed #19252 -- Added support for wheel packages.

Signed-off-by: Jannis Leidel <jannis@leidel.info>
Fixed test failures introduced in a5becad9094e5c5403b692b9a7b3a6ffaabf64a3.
Fixed #20338 - Document FQDN behavior with ALLOWED_HOSTS
Updated translation templates and removed en translations

"en" translations have been mistakenly committed in 87cc3da81.
Added myself to the committers list.
Added clarification to the docs, pointing out that unique_for_date only considers the date portion of DateTime fields.
Used ngettext in a formsets error message

Several languages will distinctly translate '%d or fewer forms'
depending on the variable.
Systematically imported wraps from functools
Fixed #18351 -- Added X-Robots-Tag header to sitemaps

Thanks Michael Lissner for the report and initial patch, and
Tom Mortimer-Jones for working on the patch.
One more changed import location of wraps
Fixed a regression introduced in 9f7a01ef2bed8c0395a970286e8f87fd7d344b3b.
Ensured that the javascript_catalog view doesn't leak translations.
Found a mistake in SQL documentation
Fixed #20305 - Added include for polls/static to MANIFEST.in in tutorial.

Thanks monuszko for the report.
Fixed #20274 - Added some clarifying section headings in the test docs.
Fixed #20177 - Corrected docs for django.test.utils.setup_test_environment.

Thanks vlad.london.uk@ for the report.
Remove outdated ForeignKey manager documentation.
Fixed #20354 -- `makemessages` no longer crashes with `UnicodeDecodeError`

Handle the `UnicodeDecodeError` exception, send a warning to `stdout` with the
file name and location, and continue processing other files.
Python 2.5 is not relevant to master.