Add new csswg color specification drafts to accepted syntaxes

[Munter]

Updated syntages for rgb/rgba:

<dfn>rgb()</dfn> = rgb( <<rgb-component>>{3} [ / <<alpha-value>> ]? ) | rgb( <<rgb-component>>#{3} , <<alpha-value>>? )
 <dfn>rgba()</dfn> = rgba( <<rgb-component>>{3} [ / <<alpha-value>> ]? ) | rgba( <<rgb-component>>#{3} , <<alpha-value>>? )

similar for hsl/hsla:

<dfn>hsl()</dfn> = hsl( <<hue>> <<percentage>> <<percentage>> [ / <<alpha-value>> ]? ) | hsl( <<hue>>, <<percentage>>, <<percentage>>, <<alpha-value>>? )
<dfn>hsla()</dfn> = hsla( <<hue>> <<percentage>> <<percentage>> [ / <<alpha-value>> ]? ) | hsla( <<hue>>, <<percentage>>, <<percentage>>, <<alpha-value>>? )

Also worth noting: ''hsl()'' and ''hsla()'' functions now accept <<angle>> as well as <<number>> for hues

See w3c/csswg-drafts@a54f8b2

[Munter]

Related:

• http://www.xanthir.com/b4iW0

[jpdevries]

How about the new 8-Digit Hexadecimal color syntax?
https://css-tricks.com/8-digit-hex-codes/

Should that be a separate issue?

[papandreou]

@jpdevries: #36

[Munter]

@jpdevries See my comment in #36 and please join the discussion if you have any input