cherry-picked commits from develop branch.

TODO

helsinki/program/admin.py

helsinki/program/models.py

helsinki/program/templates/program/current_box.html

helsinki/program/templates/program/day_schedule.html

helsinki/program/templates/program/host_detail.html

helsinki/program/templates/program/host_list.html

helsinki/program/templates/program/recommendations.html

helsinki/program/templates/program/show_detail.html

helsinki/program/templates/program/show_list.html

helsinki/program/templates/program/timeslot_detail.html

helsinki/program/templates/program/week_schedule.html

helsinki/program/urls.py