Implement command grouping (design still not satisfying)
Change interface for command groups
Refactor
Implement option grouping
Remove todos
Implement SuperCommand
chmod +x manage.sh
Use new feature of RecursiveDocument: add None instead of dummy default message
Refactor help
Be more explicit about options in help
Improve help of sub-commands and super-commands
Improve usage of sub-commands (in help)
Structure