[Reformat] sort imports

aleksis/apps/chronos/admin.py

aleksis/apps/chronos/forms.py

aleksis/apps/chronos/managers.py

...pps/chronos/migrations/0007_advanced_models_from_untis.py

aleksis/apps/chronos/migrations/0008_break_period.py

...s/chronos/migrations/0011_absence_for_groups_and_rooms.py

aleksis/apps/chronos/migrations/0014_extra_lesson.py

aleksis/apps/chronos/model_extensions.py

aleksis/apps/chronos/models.py

aleksis/apps/chronos/preferences.py

aleksis/apps/chronos/rules.py

aleksis/apps/chronos/templatetags/week_helpers.py

aleksis/apps/chronos/util/build.py

aleksis/apps/chronos/util/date.py

aleksis/apps/chronos/util/js.py

aleksis/apps/chronos/util/predicates.py

aleksis/apps/chronos/views.py