Merge pull request #14 from bvssvni/master

Upgrade to latest Rust (breaking changes)
fix compile warnings
Merge remote-tracking branch 'origin/master'
fix README
update for crates.io
Upgraded to latest Rust

* Removed unused crate attributes (license is in Cargo.toml)
* Added missing `Copy` impls
* Explicit coercion to fn
* Replaced `into_string` with `to_string`