Merge branch 'migration-path' into 'master'

aleksis/apps/chronos/admin.py

aleksis/apps/chronos/apps.py

aleksis/apps/chronos/managers.py

aleksis/apps/chronos/migrations/0001_initial.py

...chronos/migrations/0004_substitution_extra_lesson_year.py

aleksis/apps/chronos/migrations/0018_check_new_models.py

aleksis/apps/chronos/migrations/0019_remove_old_models.py

aleksis/apps/chronos/mixins.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/static/css/chronos/timetable_print.css

aleksis/apps/chronos/static/js/chronos/date_select.js

aleksis/apps/chronos/static/js/chronos/week_select.js

aleksis/apps/chronos/templatetags/__init__.py

aleksis/apps/chronos/templatetags/common.py

aleksis/apps/chronos/templatetags/week_helpers.py

aleksis/apps/chronos/util/build.py

aleksis/apps/chronos/util/chronos_helpers.py