Fix several regressions:

+ improve PropertyMaterialList::readString
+ fix transparency handling in ViewProviderPartExt
+ do not register the private member '_diffuseColor' as property because it would be exposed to the
  public where it can be modified
+ fix ViewProviderPartExt::finishRestoring() to correctly restore old project files
+ fix ViewProviderPartExt::setHighlightedFaces() to correctly show face colours if VBO is enabled
+ fix ViewProviderBoolean::updateData()
  fix ViewProviderMultiFuse::updateData()
  fix ViewProviderMultiCommon::updateData()
  fix ViewProviderCompound::updateData()
  fix ViewProviderFillet::updateData()
  fix ViewProviderChamfer::updateData()
  that all set invalid transparency values
+ Filter ShapeAppearance in ViewProviderBody::unifyVisualProperty
  because body features usually have different number of faces than the body itself
+ manually fix some bad looking auto-formatted code
+ clean up code and remove duplicated code

src/Mod/PartDesign/Gui/ViewProviderBody.cpp

@@ -427,6 +427,7 @@ void ViewProviderBody::unifyVisualProperty(const App::Property* prop) {
     if (prop == &Visibility ||
         prop == &Selectable ||
         prop == &DisplayModeBody ||
+        prop == &ShapeAppearance ||
         prop == &PointColorArray ||
         prop == &LineColorArray) {
         return;