Add Native Support for GPU's with CUDA

GPU's can provide a substantial speedup for ray tracing. Zemax started offering support for GPU's a few years ago ([See here](https://support.zemax.com/hc/en-us/articles/1500005489421-Setting-OpticStudio-to-use-an-advanced-graphics-card)). Work for this has already started in my C++ implementation: https://github.com/GNiendorf/Tracepy-Fast, where I give some plots of the expected speedup.