Auto merge of #417 - Yamakaky:update-cargo-toml, r=emilio
Auto merge of #417 - Yamakaky:update-cargo-toml, r=emilio

Improve crate metadata.

emilio/rust-bindgen,rust-lang/rust-bindgen,rust-lang/rust-bindgen,rust-lang/rust-bindgen,emilio/rust-bindgen,emilio/rust-bindgen,emilio/rust-bindgen,emilio/rust-bindgen,rust-lang/rust-bindgen