* Did a little bit of refactoring and added some docs around AsStaticStr
* Revving the version in the cargoo.toml
* Managing Cargo.toml is a bit tedious when deploying packages that depend on each other
* Updated Cargo.toml
`#[derive(AsRefStr)]` will implement `AsStaticRef<str>`, and it
enables us to get `&'static str` by `AsStaticRef::<str>::as_static()`.
This will solve #23.