Fixed #21866 -- Replaced "COMMIT" in managmement command SQL with backend hook.
Fixed some missing/extraneous new line warnings.
Fixed #19774 -- Deprecated the contenttypes.generic module.

It contained models, forms and admin objects causing undesirable
import side effects. Refs #16368.

Thanks to Ramiro, Carl and Loïc for the review.
Fixed #21823 -- Upgraded six to 1.5.2
Added missing items to 1.6.2 release notes.
Added release note stubs for 1.5.6 and 1.4.11.
Fixed #21872: Not detecting dependencies from M2M fields
Minor cleanup.
Removed superfluous uses of TransRealMixin.

The translation.override context manager cleans up after itself. As a
consequence this mixin isn't needed any more in many cases.
Removed TransRealMixin.

Fixed #21688. Refs https://github.com/django/django/pull/1147.
Fixed #21874 -- Require Django applications to have a filesystem path.

Wherever possible this filesystem path is derived automatically from the app
module's ``__path__`` and ``__file__`` attributes (this avoids any
backwards-compatibility problems).

AppConfig allows specifying an app's filesystem location explicitly, which
overrides all autodetection based on ``__path__`` and ``__file__``. This
permits Django to support any type of module as an app (namespace packages,
fake modules, modules loaded by other hypothetical non-filesystem module
loaders), as long as the app is configured with an explicit filesystem path.

Thanks Aymeric for review and discussion.
Fixed #21853 -- Fixed Manager.__module__ to properly return 'django.db.models.manager'.

The combination of BaseManager.from_queryset() and RenameMethodsBase results in
Manager.__module__ having the wrong value. This can be an issue when trying to
pickle the Manager class.
Fixed #21849 -- Included the count of silenced system checks in output.
Add an extra warning about custom save methods in migrations docs.
Fixed #21883 -- Added six.moves.xrange import

When moving code around from sql.where to lookups six.moves.xrange
import was forgotten. The xrange import is needed on Python 3.
Added tests for m2m queries with custom pk on the end models

It seems this case was fixed somewhere between 1.5.x and 1.6.x. I added
tests as I wasn't able to find any tests for these cases. Refs #21879