Non-unicode file names

[INADA Naoki]

Please use Python 3.7.

Python 3.7 has several improvements on this area.

* When PEP 538 or 540 is used, default error handler for stdio is
surrogateescape
* You can sys.stdout.reconfigure(errors='surrogateescape')

For Python 3.6, I think best way to allow arbitrary bytes on stdout is using
`PYTHONIOENCODING=utf-8:surrogateescape` environment variable.

Regards,