Jkunicode

- Read globally ignored characters from ignored_characters.json
- Use overrides file for language names
- Improve language names for alphabetical sorting

- Fix UniInfo.script return value when UniInfo.unicode is None
- Implement "Unknown" script in uniScript.get_script
- Update Unicode data to version 15
- Update CLDR data to version 42
- Add command line option to output BCP47 subtags instead of names
- Add py.typed file

Install or update via pip:
bash
pip install -U jkunicode