Add the upstream repo URL in README
Document each .json file in README.rst
Add tests for parsing <color> from CSS Color Level 3.
Merge JSON data for color tests.
Add parse_one_component_value()

It was previously implemented ad-hoc in tests.rs
Add partial color parsing (keywords only)
Add #rgb and #rrggbb color parsing.

Only functional colors are missing now: (rgb|hsl)a?
Add a Comma token.
Complete <color> parsing
Tweak float types
Typo fix #1. Thanks @jdm.