[1.4.X] Fixed #18478 - Documented how to use a mutable default in a model field.

Backport of 6e2bb344e4 from master
[1.4.x] Fixed some broken links in 1.4 docs
[1.4.x] Fixed #11185 - Expanded docs on customizing widgets; thanks fadeev for the draft patch.

Backport of a73838fde33374573b8e765dfcb0225287d396c0 from master.
[1.4.X] Added an example of using a form wizard with different templates; thanks Lorin Hochstein for the patch.

Backport of 553583958d from master
[1.4.x] Fixed #16929 - Documented how to extend UserAdmin with UserProfile fields; thanks charettes for the draft example.

Backport of 22242c510f84c53803afe2907649c892cb1b3d9a from master.
[1.4.x] Fixed #18131 - Documented ContentTypeManager.get_for_id; thanks sir_sigurd for the report.

Backport of 93e6733e4cbbdad34f1f0f59303ae01f577e4e58 from master.
[1.4.X] Fixed #18530 -- Fixed a small regression in the admin filters where wrongly formatted dates passed as url parameters caused an unhandled ValidationError. Thanks to david for the report.
[1.4.X] Fixed #13586 - Added an example of how to connect a m2m_changed signal handler.

Backport of 1360bd4186 from master
[1.4.X] Fixed #14829 - Added references to CBVs in the URLConf docs; thanks Andrew Willey for the suggestion.

Backport of acd74ffa35 from master
[1.4.X] Fixed #15325 - Added a link to RelatedManager in the ManytoManyField docs; thanks jammon for the suggestion.

Backport of 0fdfcee257 from master
[1.4.X] Fixed #18057 - Documented that caches are not cleared after each test; thanks guettli for the suggestion.

Backport of 2aaa467a2a from master
[1.4.x] Fixed #18979 -- Avoid endless loop caused by "val in PermLookupDict"

Fixed by defining __iter__ which raises TypeError. This was done to
PermWrapper earlier.

Backport of 50d573d2c0b3e17cbf1aa240b03b52e4ad0c32cd
[1.4.x] -- Fixed Python 2.5 compatibility issues
[1.4.X] Fixed #15338 - Documented django.utils.decorators

Backport of d0345b7114 from master
[1.4.X] Fixed #18413 - Noted that a model's files are not deleted when the model is deleted. Thanks lawgon for the report.

Backport of 1c03b23567 from master
[1.4.X] Fixed #19006 - Quoted filenames in Content-Disposition header.

Backport of 234ca6c61d from master
[1.4.X] Fixed #19051 - Fixed Selenium tearDownClass method; thanks glarrain for the report.

Backport of a1a5c0854f from master
Fixed #19072 -- Corrected an external file path in GeoIP docs

Thanks Flavio Curella for the report and the initial patch.
[1.4.X] Fixed #17435 - Clarified that QuerySet.update returns the number of rows matched

Backport of 6d46c740d8 from master
[1.4.x] Fixed #4501 - Documented how to use coverage.py with Django tests.

Thanks krzysiumed for the draft patch.

Backport of 7ef2781ca0ce48872e21dce2f322c9e4106d1cfd from master.