Fails if Artist has '/' in the name

[dansjackson]

Hey,

I'm getting an issue with this artist:

https://chrisstussy.bandcamp.com/track/chris-stussy-all-night-long

Artist has a special character in the name. The error is:

thread 'main' panicked at 'root directory to be created: The system cannot find the path specified. (os error 3)', src\main.rs:69:57
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[dansjackson]

I think it's related to #4