Forwardport of ae1d663b
from stable/1.8.x plus more.

- Fixed bug in get_callable() that caused resolve() to put a string
  in ResolverMatch.func.
- Made ResolverMatch.url_name match the actual url name (or None).
- Updated tests that used the string value in ResolverMatch.func, and
  added regression tests for this bug.
- Corrected test urls whose dummy view paths caused failures (behavior
  that was previously masked by this bug).

Thanks Carl Meyer for the suggestion and Alex Gaynor and Carl for reviews.

Thanks to abrahamson.j for the report, to guettli for initial work on the patch, and to David Gouldin for the new patch and test.

This applies to both our own [test] code and documentation examples. Also:
 * Moved the functions and handlers from `django.conf.urls.defaults` up to
   `django.conf.urls` deprecating the former module.
 * Added documentation for `handler403`.
 * Tweaked the URLs topic document a bit.

Thanks to pupeno and cdestigter for their great work contributing patches.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16818 bcc190cf-cafb-0310-a4f2-bffc1f526a37

Fixed #10802 -- Handle ImportErrors and AttributeErrors gracefully when raised by the URL resolver system during startup. Many thanks, IonelMaries and Bas Peschier.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16420 bcc190cf-cafb-0310-a4f2-bffc1f526a37