Fixed the generation of blender materials at import which have just a color.
Create a blender material for the decal layer on import.
Refactored the creation of classic blender materials at import time.
Make the generated classic blender materials use the correct uv layers.
Apply the clip settings to the generated classic blender materials even if they not seem to have affect in the 3d view.
Don't create a texture slot if required image isn't there.
Generate emissive texture slots for classic blender materials.