Support for OsString

[pronebird]

Hi,

Great piece of work. However I face issues using it on Windows. It forces me to go through UTF-8 String, but Windows uses UTF-16 UCS2 strings. So it's incompatible in a way with the platform.

[jonhoo]

I would also be interested in this, not for Windows support, but just so that it's possible to escape, say, a Path.