Material: Material appearance

Uses new material system for appearance

Each feature object now has a property called ShapeMaterial that
describes its physical properties. If it has a shape, it has a
material.

The ShapeColor attribute is replaced by a ShapeAppearance attribute.
This is a material list that describes all appearance properties, not
just diffuse color. As a list in can be used for all elements of a
shape, such as edges and faces.

A new widget is provided to allow the user to select materials in a
consistent fashion. It can also launch the material editor with its
more advanced capabilities.

src/Mod/Import/Gui/ExportOCAFGui.cpp

@@ -41,7 +41,8 @@ void ExportOCAFGui::findColors(Part::Feature* part, std::vector<App::Color>& col
     if (vp && vp->isDerivedFrom(PartGui::ViewProviderPartExt::getClassTypeId())) {
         colors = static_cast<PartGui::ViewProviderPartExt*>(vp)->DiffuseColor.getValues();
         if (colors.empty()) {
-            colors.push_back(static_cast<PartGui::ViewProviderPart*>(vp)->ShapeColor.getValue());
+            colors.push_back(
+                static_cast<PartGui::ViewProviderPart*>(vp)->ShapeAppearance.getDiffuseColor());
         }
     }
 }