len support for Choices.
Add e-mail to AUTHORS.
Added an UpdateOrCreateMixin for creating custom managers and querysets which have an .update_or_create() method (see Django ticket #3182).
Added missing imports to examples in README.rst
patch to issue#16
Added missing imports for UpdateOrCreateMixin
Add __len__() method to Choices
avoid plain except
deny methods for queryset copy
Fixed typo on README
Add doc note about setting db_index on StatusField; thanks Matt McClanahan for pointing this out.
Merged in jfunk/django-model-utils (pull request #9)

Add __len__() method to Choices
Merged in jgsogo/django-model-utils (pull request #5)

patch to issue #16
More straightforward, efficient implementation for InheritanceQuerySet.
Update tox.ini.
Merge pull request #16 from ryankask/choices-len

__len__ method for Choices
Resolve duplication between two pull requests for Choices.__len__.
Merge pull request #19 from DXist/master

Extra deny methods for PassThroughManager
Set use_for_related_fields=True on QueryManager.
Merge UpdateOrCreateMixin.