Add hwb() + fix max for hue

Following

harthur/color-string#8
harthur/color-convert#10

+

capping must be done before convert loop for each spaces.
Otherwise it’s not coherent with how color-convert handle overflow
(modulo).

Ref #24
For example if I set 360, this test https://github.com/harthur/color/pull/25/files#diff-e2686e2925145c11799d638b2f4706dcR84 will work with 0, not 360 (has "expected")