make fromHSL public, add toHSL

[Olaf Schmidt]

[ Matthew Woehlke, Mi., 13. Jun. 2007 ]
> It isn't. IMO your color space is correctly termed H'C'Y' :-), but at
> any rate it different from the HSL needed for khtml W3C standards and as
> used in Windows.

OK, so so the only user of making this public would currently be the Windows 
port? 

And would the Windows port use 4.0, or could this then wait until 4.1?

Olaf