Fixed #19671 -- Added warnings that null and validators are ignored for ManyToManyField.

Thanks Loic Bistuer and Tim Graham for help and review.
Fixed #22988 -- Adjusted an introspection test assertion.

Also changed test to use assertNotIn.
Fixed #22970: Incorrect dependencies for existing migrated apps
Fixed #22922: Better error message for InvalidBasesError.
Fixed #22809 -- Added model Field API reference.

Thanks to @timgraham for the review.
Fixed typo in docs/ref/contrib/gis/geos.txt.
Removed primary authors section from AUTHORS.
Fixed #13147 -- Moved User validation logic from form to model.
Fix comment
Add south upgrade note to 1.7 release notes
Added contrib.auth migration for refs #13147.
Removed docs for @permalink decorator.

It's been marked as "not recommended" since 1.6. Anyone still using it
may refer to older versions of the docs.
Fixed #22983: Alert when squashing RunPython operations with referred functions.
Bump the default iterations for PBKDF2.

The rate at which we've increased this has not been keeping up with hardware (and software) improvements, and we're now considerably behind where we should be. The delta between our performance and an optimized implementation's performance prevents us from improving that further, but hopefully once Python 2.7.8 and 3.4+ get into more hands we can more aggressively increase this number.
Removed extra newline.
Checked more precisely whether the app registry is ready.

Accounted for the three stages of population: app configs, models,
ready() methods of app configs.
Fixed #22939 -- Delayed admin_static backend detection

Thanks generalov for the report.
Added a newline to appease flake8
Fixed #23015 -- Fixed major/minor release terminology in docs.
Fixed/improved release note for refs #13147; thanks Loic.