[Color] Add Color.fromCSSColor()

Support #rgb, #rrggbb, rgb() and rgba() formats
Update the changelog
[Color] fix CS
[Color] Add support for named colors & hsl[a]()
[Color] Tweaks
[Color] fix regexps
Merge pull request #402 from vicb/csscolor

[Color] Add Color.fromCSSColor(), Color.fromHSL()
Fix jshint warnings, doc tweak.
Added NamedColors enumeration.
Remove unused dependency.
Merge branch 'master' into color
Fix documentation type for NamedColors.
Rename use of `toCSSColor` to `toCssColorString`. Update CHANGES.md.
Merge remote-tracking branch 'origin/master' into color

Conflicts:
	CHANGES.md
Renamed server to url
Fixed tests
Fixed WMS example
Fixed sky atmosphere flickering on Mac/Intel
Added backgroundColor to Scene
Updated CHANGES.md