HSV, HSL, HCY: wrap hue around during conversion to RGB

HSV, HSL, HCY: wrap hue around during conversion to RGB

In the conversions from HSV, HSL, and HCY to RGB, wrap the hue
value around to the [0,1) range, instead of producing unspecified
results outside this range.  In particular, hue=1.0 may arise when
going through lower precision, such as when decomposing/recomposing
an 8-bit image in GIMP (see gimp#5097).