Material: MaterialTreeWidget usability enhancements

Improves the MaterialTreeWidget beyond minimum viable product.

- Filters can now be filter lists to allow a variety of filtering
	options.
- User preferences allow the inclusion/exclusion of favorites and
	recents.
- Widget state such as expansion, tree expansions, etc are saved and
	restored.
- show current appearancee material when editing.
- implements a python interface

#fixes 13421: always opens full tree

src/Mod/Material/Gui/AppMatGui.cpp

@@ -34,6 +34,8 @@
 #include "DlgSettingsMaterial.h"
 #include "Workbench.h"
 #include "WorkbenchManipulator.h"
+#include "MaterialTreeWidget.h"
+#include "MaterialTreeWidgetPy.h"
 
 // use a different name to CreateCommand()
 void CreateMaterialCommands();
@@ -78,7 +80,7 @@ PyMOD_INIT_FUNC(MatGui)
 
     // load needed modules
     try {
-        Base::Interpreter().runString("import Material");
+        Base::Interpreter().runString("import Materials");
     }
     catch (const Base::Exception& e) {
         PyErr_SetString(PyExc_ImportError, e.what());
@@ -107,5 +109,18 @@ PyMOD_INIT_FUNC(MatGui)
     // add resources and reloads the translators
     loadMaterialResource();
 
+    Base::Interpreter().addType(&MatGui::MaterialTreeWidgetPy::Type,
+                                matGuiModule,
+                                "MaterialTreeWidget");
+
+
+    // Initialize types
+
+    MatGui::MaterialTreeWidget::init();
+
+    // Add custom widgets
+    new Gui::WidgetProducer<MatGui::MaterialTreeWidget>;
+
+
     PyMOD_Return(matGuiModule);
 }