Colour spaces:
	LMS
	L'M'S'
	ICtCp
	YCbCr
	TSL
	Y'UV
	Hunter 1948 color space (see Wikipedia article on CIELAB)
	CIELCh (CIEHLC) (see Wikipedia article on CIELAB)

Support for generic additive colour spaces (3 channels and more)
Support for generic subtractive colour spaces (3 channels and more)

GPU accelerated functions:
	int libcolour_convert_en_masse_f(const libcolour_colour_t* from, const libcolour_colour_t* to, size_t n, ...)
		Where `...` normally is `float* ch1, float* ch2, float* ch3`.
	int libcolour_convert_en_masse_d(const libcolour_colour_t* from, const libcolour_colour_t* to, size_t n, ...)
		Where `...` normally is `double* ch1, double* ch2, double* ch3`.