Fixed #22579 -- Corrected validation for email to reject trailing slash

Thanks to Claude Paroz for the report and patch and Tomasz
Paczkowski for the review.
Fixed #22490 -- removed obsolete ComplexFeed class from syndication_tests

It was previously used in a test that was deprecated and then removed, this cruft can be removed now.
Removed an unused import
Fixed #22531 -- Added tree.Node.__repr__ and tests for the class.

While Node class has a useful `__str__`, its `__repr__` is not that
useful. Added a `__repr__` that makes use of the current `__str__`.
This is especially useful since the more popular `Q` class inherits
`tree.Node`. Also created new tests that cover most of `Node` class
functionality.
Refs #21798 - Modified error number to provide room for future expansion.
Removed --skip-scripts from extras/Makefile.

This is the default now, see https://bitbucket.org/pypa/wheel/commits/c29f82b4cf76df71f8d55b0f825af6063d3b9892
Fixed #18389 -- Fixed the way contribute_to_class is called

Now this method is only called only if the object is an instance.
This allows to have field classes as model class attributes.
Fixed #22622 -- Added ugettext_lazy import in docs
Fixed #22167 -- Improved documentation on context processors

Clarified the explanation on the order in which user provided variables
to render_to_response, RequestContext and context processors are
loaded.
Fixed #22266 - quote PK before redirecting away from add_view (django.contrib.admin)
Fixed #15716 - Authentication backends can short-circuit authorization.

Authorization backends can now raise PermissionDenied in "has_perm"
and "has_module_perms" to short-circuit authorization process.
Fixed #21905 -- Add info message if DateField or TimeField use a fixed value
Fix storing of binary fields and unicode textfields for Oracle/Python3
Fixed typo.
Fixed #22625 -- Normalized make_aware/naive errors.

Also added tests for is/make_aware/naive.

Thanks Tom Michaelis for the report.
Optimized make_aware/naive by removing redundant checks. Refs #22625.

Also added tests with pytz and removed misplaced tests.
Added stub release notes for 1.6.6.
Fixed #16245 -- Included traceback in send_robust()'s response

Exceptions from the (receiver, exception) tuples returned by
``send_robust()`` now have always their traceback attached as their
``__traceback__`` argument.
Fixed jenkins breakage, apparently migrations need a models module.

Workaround for now, Andrew will look into it.
Merge pull request #2346 from Markush2010/ticket21905

Fixed #21905 -- Add info message if DateField or TimeField use a fixed value