[bug 907872] Add analytics group and scaffolding

* added contenttype, permission and group for analyzers
* added dashboard pages for "analyzers" and "spam" with filler text
* switch to Django nose test runner
* rework dashboard template hierarchy
* adds a 403 template
* requires the analytics.can_view_dashboard permission to see the
  analytics_dashboard and spam_dashboard views
* switches to using "first_name" everywhere we greet someone
* fixes the dashboard link so that /, /dashboard and /dashboard/
  all work and go to the same place