Update CSS Colors to latest WC3 Spec

The current color list in the CSS Bundle is outdated as it lists named colours as invalid (i.e. aliceblue, royal blue, etc.)

Updating to the latest working draft (https://www.w3.org/TR/css-color-4/) would be great as it'll simplify the named color section. It also includes 'currentcolor' which is already implemented in most major browsers.
