Moved ServerHandler helper class to tests.

It has been only used in the builtin_servers tests since Django 1.4.
Improve migrations/schema docs
Fixed #22369 -- Added count parameter to assertTemplateUsed
Fixed #22356 -- Added a check to make sure unique_together fields are local.
Refs #18586 - Refactored model get_or_create test.

Refactored get_or_create test into several smaller test functions across two
different test classes. Also converted the comments over to docstrings.
Merge pull request #2553 from liavkoren-vmfarms/ticket_18586

Ticket 18586
Fixed #22392 -- Corrected deployment instructions for Apache 2.4.

Thanks zjcheah at yahoo.com for the report.
Fixed #22443 -- Document smtp.EmailBackend.timeout default value

Django 1.7 introduces a new timeout parameter for the SMTP email backend:
http://docs.djangoproject.com/en/dev/topics/email/#django.core.mail.backends.smtp.EmailBackend.timeout

However, there was no mention of the default value for this parameter.
Added RemoteUserMiddleware to middleware reference page.
Added a note regarding django.contrib.auth.authenticate.

Thanks Josh Brown for the suggestion.
Fixed #22453 -- Corrected DoesNotExist message in docs.

Thanks Eugenio Cano-Manuel.
Fixed #22457 -- Fixed contributing guide w/o github set-up

The published commnand was not working when the user did not have
the git client set-up with the public-key. Changed the contributing
guide to clone it from https instead.
Fixed spelling errors in documentation.
Fixed #22460 -- Explicity remove constraints when dropping a related field.
Fixed flake8 warnings introduced in recent commits.
Fixed #22455 -- Documented return values for send_mail and send_mass_mail
Fixed #22434 -- Retain ordering on related sliced subqueries.

Thanks maciej.pawlisz for the report, and charettes for the review.
Fixed #22220 -- Added more examples to reverse() documention.

Thanks EvilDMP for the suggestions.
Fixed #22378 -- Updated \d to [0-9]+ in urlpatterns of docs and tests.

Thanks tomwys for the suggestion.
Revert "Fixed #22401 -- Deprecated regular expression parsing of initial SQL in favor of installing sqlparse."

This reverts commit 071c9337750b296d198cced56f3ffad0e176afb6.

This introduced a regression on MySQL and custom SQL is deprecated.