Change product schema to Lars version.
Make work topic model feature complete.
Fix handling None values for WorkTopic.period.
Complete work topic dialog UI.
Fix who combobox selection not working.
Remove debug prints.
Show work topic values from the database.
Allow saving work topics.
Fix work topic icons.
Disable unused controls in work topic dialog.
Add work topic creation and deletion actions.
Ensure an area has been selected.
Fix work topic deletion.
Add work topic creation action to area context menu.