Merge branch 'upgrade_to_django-1.11' into '1.4.x'

.gitlab-ci.yml

beat/web/accounts/urls.py

beat/web/algorithms/views.py

beat/web/attestations/views.py

beat/web/backend/views.py

beat/web/databases/views.py

beat/web/dataformats/serializers.py

beat/web/dataformats/views.py

beat/web/experiments/serializers.py

beat/web/experiments/views.py

beat/web/libraries/views.py

beat/web/navigation/views.py

beat/web/plotters/serializers.py

beat/web/plotters/views.py

beat/web/reports/views.py

beat/web/search/models.py

beat/web/search/views.py

beat/web/settings/settings.py

beat/web/statistics/views.py

beat/web/team/views.py