Add feature to convert blender internal materials to cycles and back

[david-tran-archilogic]

Use Case:
A user downloads an Archilogic model as a blend file and wants to manipulate the materials in cycles.
When exporting the file as a .obj file to import the model back into Archilogic, the materials are exported from blender internal and the changes in cycles are not taken into account.

Suggestion:
Add a feature to convert material information of an Archilogic blend file from cycles to blender internal (and back) to make sure that you don't lose material information such as assigned textures when trying to export the model to a format like OBJ.