Removed bogus, ineffective 'U' flag from codecs.open() call.
Use the new implementation of `six.with_metaclass`.

No more `NewBase` horrors.

Thanks to bendavis78 for his work on merging this into six.
Fixed #22447 -- Make sure custom model bases can be migrated.

Thanks to cdestigter for the report.
Fixed #22511 -- Added args to migrations management commands.
Removed unused import.
Fixed #22442 -- Provided additional documentation regarding id fields clashing.

Thanks benjaoming for raising the issue and Loic for the examples.
Fixed #22537 -- Add tests and improved docs for field subclass with choices.
Fixed #22474 -- Made migration recorder aware of multiple databases

Thanks Tim Graham for the review.
Refactored DjangoTranslation class

Also fixes #18192 and #21055.
Fixed #19195 -- Allow explicit ordering by a relation `_id` field.

Thanks to chrisedgemon for the report and shaib, akaariai and
timgraham for the review.
Fixed #22485: Include all unmigrated apps in project state by default.
Fixed #22546 -- Removed idioms in tutorial 2.

Thanks bjb at sourcerer.ca for the suggestion.
Cleanup failing test w/contenttypes and remove useless graph load
Fixed #22547 -- Added some links to tutorial 2.

Thanks bjb at sourcer.ca for the suggestion.
flake8 fixes.
Fixed #22539 -- Copied exclude argument in Model.full_clean() to prevent side effects.
Fixed #22551 -- Made oracle backend method Python 3 compatible

Thanks fatal10110 at gmail.com for the report. The fix is 1.6-only
because that code has been refactored in 1.7 (6983201cfb).
'Docs-only' forward port of 120a98120 from 1.6.x.
Fix migration autodector to work correctly with custom deconstructed values
Fixed #22558 -- Added missing word in contributing docs
Fixed #22533 — allowed `label_suffix` to be overriden by fields

Fields can now receive the `label_suffix` attribute, which will override
form's own `label_suffix`.

This enhances the possibility to customize form's `label_suffix`, allowing
to use such customizations while using shortcuts such as
`{{ form.as_p }}`.

Note that the field's own customization can be overriden at run-time by
using the `label_prefix` parameter to `BoundField.label_tag()`.

Refs #18134.