added methods to Color::RGB to calculate the contrast between two RGB colors
added methods to Color::RGB to calculate the contrast between two RGB colors
contrast is not considered public for some reason
added additional contrast method which implements e2000 method for computing contrast. Added tests for this and existing #contrast
added e2000 contrast method and hand-made contrast method
putting lab stuff into its own area, and correcting references to lab objects to reflect
left #closest_match same as it was, but fully qualified #delta_e94 reference