Uroboros

Fix

- Fix `argparse.ArgumentError` when callling `uroboros.Option.get_parser()` multiple times ( 40 )
- Fix to use return instead of raise ( 39 )

Fix

- `get_options` returns a new list of `uroboros.Option` instead of its class attribute directly ( 37 )

Fix

- Fix to use `Command.get_options()` correctly.

New features

- Hook function
- 5
- 25
- Bulk add commands
- 12

Changes

- `Command.get_sub_commands` is renamed to `Command.get_all_sub_commands`. Now, `get_sub_commands` returns specified subcommands.
- `Command.add_command` accept multiple command instance ( 12 )
- Check the arguments of `Command.add_command` are an instance of `Command`.

- Support nested sub commands
- Support sharing options among some commands
- Pure python implementation