Fixes issue #40 Checks for instance of CategoryBase instead of Category.

There are still some template tags that won't work with subclasses. Need a better solution for those tags.
Version bump to 1.0.4b2
Minor fix to example app
Bunped version to 1.0.4 final
use ugettext_lazy
Merge pull request #41 from numerodix/master

Using ugettext_lazy
make it optional to register in admin
stylistic fixes and docs
Merge pull request #42 from numerodix/master

make Category registration in admin optional
Updated CREDITS, docs and bumped version to 1.0.5
Merge pull request #36 from nephila/master

Document an upgrade path from 1.0.2 to 1.0.3 (issue #35)
Merge pull request #45 from nephila/master

Format error in README.rst
Updated the credits to add Iacopo Spalletti
Fixes Pull Request #37 Adds notification in the readme regarding issue with South version 0.7.4
Update to template tags to include ways to retrieve an object from a model other than Category.
pep8 cleanup
Fixed some Django 1.4 cosmetic issues
Template tags now work with any derivative of CategoryBase. Recognizes the "using" param to specify the model to use.
Fixed an incorrect include in the example
Updated and rendered docs