Support for Windows

[JackMordaunt]

I went to try out this tool on Windows and it fails to compile xdg (naturally).

I understand if not supporting Windows is intentional, however if not, it should be simple to use a cross platform crate for handling configuration directories.

[danobi]

It wasn't necessarily intentional (as in I don't have anything against windows). Just that I don't use it and don't have any windows computers.

If you'd like to send a PR to support windows, I'd probably take it as long as it's not too invasive and there's a way to test windows support in CI.