Django 1.6 upgrade and cleanup

Lots of changes! Some require changes to configuration. Intention is to update Sikteeri to be more maintainable in the future and easier to approach as a new developer.

* Upgrade from Django 1.4 to 1.6
* Requires now Python 2.7
* Upgrade to Gunicorn 19.0.0
* Upgrade to South 1.0
* Add django-debug-toolbar (DEBUG=True only)
* Fixed static files in development - need to use collectstatic for production
* Getting rid of CGI update script - let's use Jenkins or Fabric for deployment
* Virtualenv setup is now cleaner - compatible with python3 virtualenv. Now placed outside project directory in ~/env/sikteeri
* Get rid of Lighttpd development server
* Move manage.py to top level - Django best practice
* Update WSGI script and manage.py from Django startproject defaults
* Explicitly set Membership.public_memberlist to default to False
* Upgrade to class based generic views
* Clean up settings - ready to go for development!
 - Removed local_settings.py crud. Need to override settings file for prod
* Add clickjacking prevention headers

Logging still needs work before ready for production...