Fixed #19749 -- Documented ending param to command's self.stdout/err

Thanks xian at mintchaos.com for the report.
Fixed #19699 - Removed "Please see the release notes" from versionadded/changed directives

Also bumped django_next_version back to 1.6 so those
annotations are described as "the development version"
in the docs.

Thanks Aymeric for the patch.
Added tests for some sql_* management commands
Made modwsgi groups_for_user consistent with check_password

2b5f848207b1dab35afd6f63d0107629c76d4d9a based its changes on #19061
that made the is_active attribute mandatory for user models.
The try/except was not removed for the groups_for_user function.

refs #19780
Merge branch 'master' of git://github.com/django/django