Rust library for converting RGB colors to the CIE-L*a*b* color space

```rust extern crate lab; use lab::Lab;

let pinkinlab = Lab::from_rgb(&[253, 120, 138]); // Lab { l: 66.6348, a: 52.260696, b: 14.850557 } ```

```rust extern crate lab; extern crate image;

use lab::Lab; use image::Rgba;

let pixel: Rgba = Rgba { data: [253, 120, 138, 255] }; let lab = Lab::from_rgba(&pixel.data); // Lab { l: 66.6348, a: 52.260696, b: 14.850557 } ```