Add equality support for Project/ModelState
Add RunPython migration operation and tests
Make sqlmigrate ignore the RunPython operation
Allow callables as the argument to RunPython
Remove most errors when running migration tests twice
Updated a code block to use the emphasize-lines Sphinx option
Add reverse_code optional argument to RunPython
Fixed wording in unit tests documentation.
Fixed #21126 -- QuerySet value conversion failure

A .annotate().select_related() query resulted in misaligned rows vs
columns for compiler.resolve_columns() method.

Report & patch by Michael Manfre.
Fixed #3871 -- Custom managers when traversing reverse relations.
Fixed #17671 - Cursors are now context managers.
Fixed #20364 -- Changed urlize regexes to include quotation marks as punctation.

Thanks to EmilStenstrom for raising this, and to Chris Piwoński for all of the fixes and most of the tests.
Enabled migrations.Operation to control their own output.