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
Yep, leave it at `360`. We can work out the inconsistency later perhaps. I think an overflow like 400 should become 360.