Fixed #19896 -- Committed after clearing cache in the database.
Removing unneeded tearDown code.
Add sqldropindexes to manage

Change patch from https://code.djangoproject.com/ticket/5568
to work on modern Django.
Add special case for MySQL which has different syntax for DROP INDEX.
Add unit tests for the new functionality.
Revert "fixes #19263" - Fails if not SQLite

This reverts commit 2b76f19f2b89ac96bae2a169d71b23553c8101c7.
Made changes asked in review by HonzaKral

Add documentation for new command in django-admin.
Merge pull request #817 from rybaktomasz/ticket_5568

Fixes #5568 -- DROP INDEX subcommand
Fixed a few ResourceWarnings.
Fixed #11295: If ModelAdmin.queryset returns a filtered QS don't require a 2nd count call

Original patch rewritten, added tests and get_filters_params method for ChangeList class.
Thanks Alex for the report.
URL-encoded URLs in FlatPage.get_absolute_url.
Fixed #18862 -- Honored script prefix in FlatPage.get_absolute_url.
Merge pull request #820 from viciu/11295

Fixed #11295: If ModelAdmin.queryset returns a filtered QS don't require a 2nd count call
Fixed #19810 -- MemcachedCache now uses pickle.HIGHEST_PROTOCOL
Fixed minor rst formatting glitch.
Fixed #16302 -- Ensure contrib.comments is IPv6 capable

Changed the ip_address field for Comment to GenericIPAddressField. Added
instructions to the release notes on how to update the schema of existing
databases.
Merge pull request #819 from erikr/master

Fixed #16302 -- Ensured contrib.comments is IPv6 capable.
Fixed #9084 - Best approach for an OS to atomically rename the session file.
Fixed #19253 -- Extracted template cache key building logic

Introduced a public function
django.core.cache.utils.make_template_fragment_key
Thanks @chrismedrela for fruitful cooperation.