Add support for exotic color notations

[bartveneman]

TinyColor doesn't support converting the following formats:

color: hsl(270deg, 60%, 70%);
color: hsl(4.71239rad, 60%, 70%);
color: hsl(.75turn, 60%, 70%);
color: rgba(1e2, .5e1, .5e0, +.25e2%);

[bartveneman]

Colord is doing a great job now, or will pretty soon.