CIE Picker: Add option to limit fixtures to smallest common Color Space#105

0.9.0 Beta 1 (b68a9dd)

Select fixture (additive mixing) with different color space in CIE picker and move around.

By selecting multiple fixtures with different reference values, normal operation involves displaying the CIE space of the fixture with the highest spectrum. In selection, the value coincides if all the fixtures are able to reproduce the value, when it is outside the spectrum of the fixture with the smallest space, the selection is divided radially following the closest value.