https://crates.io/crates/structopt
https://docs.rs/structopt
https://crates.io/crates/structopt-derive
https://docs.rs/structopt-derive

https://github.com/TeXitoi/structopt

https://www.reddit.com/r/rust/comments/5u3sb5/structopt_when_clap_meet_custom_derive/

whatsnew
0.2.0
https://www.reddit.com/r/rust/comments/7wnw2f/structopt_v020_is_out/