Monty

- Revert changes to json.py for now.

- Misc bug fixes for jsanitize (Andrew-S-Rosen).

- Fix MSONable.REDIRECT when module name changed (janosh)
- Add native support for enums in jsanitize (FabiPi3)
- Make jsanitize(recursive_msonable=True) respect duck typing (Andrew-S-Rosen)
- Add optional arg target_dir in compress_file and decompress_file to allow specify target path (DanielYang59)
- Add MontyEncoder/MontyDecoder support for pathlib.Path (Andrew-S-Rosen)
- Add an optional arg deadline to dev.deprecated to raise warning after deadline (DanielYang59)

- Bug fix for symlinks when using copy_r (Andrew-S-Rosen)

- Bug fix for Enum subclasses with custom as_dict, from_dict (jmmshn)

- Fix import of optional libraries.