Support of Blender Cycles Mix Shader
The mix shader is often used in cycle. It allows one to mix the output of two shaders (linear interpolation) to emulate complex material.
Currently the python script to export a cycle scene does not support this shader, leading to many glossy-like material exported as lambertian. Furthermore, this shader is often used to combine a texture (as a diffuse component) and a glossy BSDF.
It seems important that the script handles this kind of shaders.