xdg crate is not supported on Windows

[udoprog]

The xdg crate is not supported on Windows, and currently results in:

   Compiling ncspot v0.1.0 (E:\work\repo\ncspot)
error[E0433]: failed to resolve: could not find `BaseDirectories` in `xdg`
  --> src\playlists.rs:58:29
   |
58 |         let xdg_dirs = xdg::BaseDirectories::with_prefix("ncspot").unwrap();
   |                             ^^^^^^^^^^^^^^^ could not find `BaseDirectories` in `xdg`

error[E0433]: failed to resolve: could not find `BaseDirectories` in `xdg`
  --> src\playlists.rs:85:29
   |
85 |         let xdg_dirs = xdg::BaseDirectories::with_prefix("ncspot").unwrap();
   |                             ^^^^^^^^^^^^^^^ could not find `BaseDirectories` in `xdg`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0433`.
error: Could not compile `ncspot`.

To learn more, run the command again with --verbose.

This is due to this crate level cfg attribute:
https://github.com/whitequark/rust-xdg/blob/master/src/lib.rs#L1

The directories crate is a portable alternative to this crate:
https://docs.rs/directories/1.0.2/directories/