Fixes #33 redirect after user registration no longer raises a 404

By default django-registration redirects to user profile page and
there is not way to change that. At this point in the development
we will not be using user profiles. I subclassed RegistrationView,
provided by django-registration, and shadow its get_success_url
method.
Categories are now required to create a resource.
Fixes #36 You can not filter down by a filter that has already been
applied.
Adding the same filter over and over again was possible.
Added a new context variable "filters" and rename the old context
variable "filters" to selected_facets. Checking in the template
to see if a filter has been applied can be done by checking if
the filter is in the context varaible filters.
Made data types a required field in the admin for the resource model.
Changed doc string for get_selected_facets method.
Removed no longer needed statements from get_selected_facets method.
Added filter |title to field name in the active filters search box.
Merge pull request #37 from openrural/fixes/#36-repeat-querystring

Fix for repeated queryset parameters when applying same facet multiple times
Merge pull request #35 from openrural/fixes/#33-user-profile-page

Redirect after user registration no longer raises a 404
Merge pull request #38 from openrural/homepage-work

Homepage work
Adds feature_images variable to homepage.

Feature images have a foreignkey to resource to link one to the other.
Added sorl-thubnail to the list of install apps and fixed a problem
with the admin interface.
Merge branch 'master', remote-tracking branch 'origin'
commit to update master
Merge branch 'master' of github.com:openrural/open-data-nc
merging
Added static pages for footer links.

Html documents for this pages can be found inside the directory "pages".
solr-rebuild-schema.sh was failing to execute in a Mac.

sed command modified to check for type of box (linux or mac)
and correct command for each OS runs.
merging
retry merge
Merge remote-tracking branch 'origin/master' into homepage-work