wrap long words in field labels on admin forms, closes #18755

Otherwise, words overlap into the fields themselves, which makes the labels
unreadable.
Fixed #19549 - Typo in docs/topics/auth/default.txt
Fixed #19547 -- Caching of related instances.

When &'ing or |'ing querysets, wrong values could be cached, and crashes
could happen.

Thanks Marc Tamlyn for figuring out the problem and writing the patch.
Minor fixes in the known_related_objects tests.

* Fixed JSON indentation.
* Avoided relying on implicit ordering.
Fixed PR 478 -- Removed superfluous try/except block.
Update doc example for overriding change_form.html

Slightly reworded another related paragraph for clarity, too.
Fixed #19516 - Fixed remaining broken links.

Added -n to sphinx builds to catch issues going forward.
Fixed #19545 -- Make sure media/is_multipart work with empty formsets
Updated comment about PostGIS bug 2035

PostGIS 2.0.2 has been released on December 3rd 2012, with the
fix included.
Fixed #19134 -- Allowed closing smtp backend when the server is stopped

Thanks Sebastian Noack for the report and the initial patch.
Fixed #19382 -- Stopped smtp backend raising exception when already closed

Thanks Sebastian Noack for the report and the initial patch.
Added documentation for the 'db' argument of the post-syncdb signal.
Replaced deprecated sslerror by ssl.SSLError

The exact conditions on which this exception is raised are not
known, but this replacement is the best guess we can do at this
point.
Fixed #19192 -- Allowed running tests with dummy db backend

Thanks Simon Charette for the initial patch, and Jan Bednařík for
his work on the ticket.
Fixed #19562 -- cleaned up password storage docs
Fixed #12914 -- Use yaml faster C implementation when available

Thanks Beuc for the report and the initial patch.
Fixed #19173 -- Made EmptyQuerySet a marker class only

The guarantee that no queries will be made when accessing results is
done by new EmptyWhere class which is used for query.where and having.

Thanks to Simon Charette for reviewing and valuable suggestions.
Tests for various emptyqs tickets

The tickets are either about different signature between qs.none() and
qs or problems with subclass types (either EmptyQS overrided the custom
qs class, or EmptyQS was overridden by another class - values() did
this).

Fixed #15959, fixed #17271, fixed #17712, fixed #19426
Fixed #19571 -- Updated runserver output in the tutorial
Created special PostgreSQL text indexes when unique is True

Refs #19441.