Material: Material Preferences

Updates the material preferences including selecting a default material

Preferences adds some options for what gets displayed in the Materials editor.
The option to use the legacy editor is removed in favour of the new
editor.

A new preference page has been added that allows the user to select a
default material. This will then be assigned to any newly created object. In
support of this, a new widget PrefsMaterialTreeWidget has been added as an
extension of the MaterialTreeWidget to automatically save and restore the
selected material.

src/Mod/Material/Gui/AppMatGui.cpp

@@ -31,6 +31,7 @@
 #include <Gui/Language/Translator.h>
 #include <Gui/WidgetFactory.h>
 
+#include "DlgSettingsDefaultMaterial.h"
 #include "DlgSettingsMaterial.h"
 #include "Workbench.h"
 #include "WorkbenchManipulator.h"
@@ -105,6 +106,8 @@ PyMOD_INIT_FUNC(MatGui)
                                                  QObject::tr("Material workbench"));
     new Gui::PrefPageProducer<MatGui::DlgSettingsMaterial>(
         QT_TRANSLATE_NOOP("QObject", "Material"));
+    new Gui::PrefPageProducer<MatGui::DlgSettingsDefaultMaterial>(
+        QT_TRANSLATE_NOOP("QObject", "Material"));
 
     // add resources and reloads the translators
     loadMaterialResource();