Aggregates return an explicit None if there is no data to aggregate, and dict's get method
only returns teh default if the key does not exist.

Closes #43.

Closes #59.

- Show substitutions only for one day instead for one week

Current status: Time and weekday headings are shown

- Add custom stylesheets from SchoolApps to timetable.css
- Customize plan.html for new data structure
- Change sorting of lessons from column-based to row-based system to support CSS and HTML structures better
- Add plan.html instead of tt_week.html to timetable view
- Add short variants of weekday names

- Add a links to quick launch
- Update url schemas for timetable to remove the need of get params
- Add i18n and reformat

mirabilos authored 5 years ago and mirabilos committed 5 years ago

Make all files, except the shell scripts with shebang, not executable.

Advances BiscuIT-ng#115.

Advances BiscuIT-App-Alsijil#46.

Add next() method to LessonPeriod QUerySet to get the n-th item before/after a reference lesson. Advances #34.