ttt: restore import local_settings
ttt: settings: fix context processors
ttt: requirements: add psycopg2
ttt: tracking: initial migration
ttt: settings: restore some more things that were dropped when moving to 1.7
ttt: tracking: views: use json instead of simplejson

simplejson was dropped from Django 1.7
ttt: tracking: views: use content_type instead of mimetype

Django 1.7 changed mimetype to content_type for HttpResponse.