Useage : "...[.... csg*]" equals "current mesh -CSG- the mesh in the braces".
Keywords :  CsgUnion<csgu>, CsgSubstract<csgs>, CsgAnd<csga>, CsgXor<csgx>
TODO : cleanup useless code.
TODO : Some bugs are still present, some face that disappear should not.
TODO : Correct epsilon useage (see geometry files).
TODO : Coplanar face are not handled -at all-.
TODO : Vertex count goes through the roof in case of a Xor.

TODO : second pass on coding-style, and some tweak & usage modification.

and add a simple unit test function.

Now takes an optional shader

reorganise the CIE-1931 and CIE-1964 tables.

a wavelength to saturated xyY function based on the standard observer
data.

white value in case we want to convert XYZ to L*a*b* with something
else than D65.

add XYZ to xyY conversion (which gives us a pretty accurate xy graph of
the sRGB gamut), and normalise XYZ using a D65 white point.

function for CIE L*a*b* values.

files on some Unix systems.

subtelties to avoid polluting Doxygen.