Ability to add multiple lenses at the same time

[CodeFHD]

Currently, the addon is limited to create a singlet or cemented doublet lens. The internal raytracing option can not take into account other, previously created lenses.

Add the options to create a more complex lens system and display a full sequential raytrace thrugh it.

[CodeFHD]

One solution has been added by featuring some zmx-import.

Will leave the issue open for further changes. The original idea was to provide an interface in Blender where multiple lenses can be added directly, or lenses linked with ones previously generated.