make fromHSL public, add toHSL

[Matthew Woehlke]

Currently there is HSL code in khtml. Windows uses HSL for the color 
picker. How would people feel about making fromHSL/toHSL public so that 
KColorDialog can also use them on Windows? (and... so that any other 
interested parties can use them, presumably...)

-- 
Matthew
Any sufficiently advanced bug is indistinguishable from a feature.
(...with apologies to Arthur C. Clarke)