Calculates rgb values from spectra based on human color matching functions
(CMF) or chromaticity coordinates (CC). A CMF takes into account luminous
sensitivity, while a CC only the color hue. This function, in contrast to
that in package pavo does not normalize the values to equal luminosity, so
using a CMF as input gives the expected result. Another difference is that it
allows the user to choose the chromaticity data to be used. The data used by
default is different, and it corresponds to the whole range of CIE standard,
rather than the reduced range 400 nm to 700 nm. The wavelength limits are not
hard coded, so the function could be used to simulate vision in other
organisms as long as pseudo CMF or CC data are available for the simulation.