Added the AddIndex and RemoveIndex operations to use them in migrations.

Thanks markush, mjtamlyn, timgraham, and charettes for review and advice.

Thanks Tim Graham for the review.

Since 859fc020, this is no longer needed.

Thanks Tim Graham for the review.

Thanks Tim Graham for the initial patch.

SQLite disgresses from the SQL standard by ignoring case of quoted identifiers.

Thanks to laozzzi for the report and Tim for the review.

Thanks Huynh Thanh Tam for the initial patch and Claude Paroz for review.

Thanks Julien Hartmann for the report.

Fixed #26729 -- Allowed overriding a form field's label/help_text in Form.__init__() for TabularInline.

Thanks Yegor Kazantsev for the report and the initial patch.

Since Django 1.8, firstof escapes its output.

It was removed in 785cc71d only because
it was untested and unused in Django itself, however, some third-party
apps use it.

Fixed #26643 -- Prevented unnecessary AlterModelManagers operations caused by the manager inheritance refactor.

This also makes migrations respect the base_manager_name and
default_manager_name model options.

Thanks Anthony King and Matthew Schinckel for the initial patches.

Also used ALLOWED_HOSTS to check for external hosts in assertRedirects().

Thanks François-Xavier Thomas for the report.

Thanks Simon Charette for review.

This reverts commit 1b407050 as it
introduces a regression in the test for refs #26772.

Fixed a regression in 2f16ff5a.

Thanks Tim Graham for the review.

Regression in 86573861

Thanks Tim Graham for the review.

This reverts commit a52a531a due to
regressions described in refs #26772.