add "learning" as optional category for Article model
toc links for articles in learning category
add new tags app for split tagfields
add split tagfields to Code model
support for split tagfields in code list view
template support for split tagfields
Merge pull request #149 from ryanpitts/development

Adding "Learning" category for articles
remove original django-taggit
add forked version of django-taggit
update django-taggit fork
add split tag fields to Article model and admin
split tag handling in article queryset
split tag support for article rss
split tag queries in Code view
split tag support for Article and Code feeds
add filter_queryset_by_tags util
switch Article and Code list views to use filter_queryset_by_tags
get rid of stray print statement
patches to django-taggit
split tag queryset utils into smaller pieces