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/PartDesign/Gui/Workbench.cpp

@@ -237,6 +237,7 @@ void Workbench::setupContextMenu(const char* recipient, Gui::MenuItem* item) con
 
             if (Gui::Selection().countObjectsOfType(App::DocumentObject::getClassTypeId()) > 0) {
                 *item << "Std_Placement"
+                      << "Std_SetMaterial"
                       << "Std_ToggleVisibility"
                       << "Std_ShowSelection"
                       << "Std_HideSelection"