Fixed #14894 -- Ensure that activating a translation doesn't run into threading issues.

Thanks to maxbublis for the report and sergeykolosov for the patch.
Fixed #15201: Marked CACHE_MIDDLEWARE_ANONYMOUS_ONLY as deprecated
Merge branch 'master' of github.com:django/django
Merge pull request #1127 from filias/20142

Fixed #20142 -- Added error handling for fixture setup
Fixes a Python 3.x regression introduced in a19e9d80
Merge pull request #1135 from ambv/model_validation_fix

Fixes a Python 3.x regression introduced in a19e9d80
Fixed #20284 - Added a note about DEBUG in static file docs.

Thanks wim@ for the suggestion and Nicolas Noé for the patch.
Fixed #13958 -- problem reporting exception from \r-line-ended file

Thanks petrvanblokland for reporting and saz for the patch
Fix state tests a little
Add missing imports and models to the examples in the the model layer documentation
Add missing imports and models to the examples in the view layer documentation
Add missing imports to the examples in the 'First Steps'
add Leandra Finger, Silvan Spross and Marc Egli to AUTHORS
Fixed ff881aef on Python 3.
Fixed #20234 and #20236 -- SingleObjectMixin fixes

Added object on SingleObjectMixin returned context,
some code clanup.
Fixed #20440 -- Ensured CharField's max_length/min_length are integers
Fixed #20246 -- Added non-breaking spaces between values an units
Updated contrib.humanize translation template
Fixed #20004 -- Moved non DB-related assertions to SimpleTestCase.

Thanks zalew for the suggestion and work on a patch.

Also updated, tweaked and fixed testing documentation.
Typo in comment