Revert change to the default Form.clean()

This means it doesn't break for people who are doing
`cleaned_data = super(FooForm, self).clean()`.
Added more on @cached_property, refs #20870
Merge pull request #1457 from jaimeirurzun/master

Clarified meaning of models.User.is_authenticated()
Added an anchor for django.forms.Form.clean in docs
Improved queryset handling and docs for (Single|Multiple)ObjectMixin.
Merge pull request #1460 from loic/ObjectMixins.get_queryset

Improved queryset handling and docs for (Single|Multiple)ObjectMixin.
Fixed #12288 -- Added unique validation for INSTALLED_APPS
Fixed test failures introduced by #12288
Fixed test failures on Python 3 - refs #12288
Merge remote-tracking branch 'core/master' into schema-alteration

Conflicts:
	django/core/management/commands/flush.py
	django/core/management/commands/syncdb.py
	django/db/models/loading.py
	docs/internals/deprecation.txt
	docs/ref/django-admin.txt
	docs/releases/1.7.txt
Fixed #9057 -- Added default_permissions model meta option.

Thanks hvendelbo for the suggestion and koenb for the draft patch.
Document new field API in release notes
Merge remote-tracking branch 'core/master' into schema-alteration

Conflicts:
	django/db/models/options.py
SQLite test fix -- refs #9057
Fixed #18356 -- Gave the test client signals.template_rendered call a unique dispatch_uid

This prevents the test client context from being lost when the client
is used in a nested fashion.
Remove useless override of self.style
utils.importlib is deprecated
Remove other color_style override
Remove commented-out print
Remove pointless fetch_results param