Using of wxWidgets 3.1.6 WIP:

* Create Cache of wxBitmapBundles instead of wxBitmaps
* Use wxBitmapBundles instead of wxBitmap for most of Widgets
* Use empty bitmabundles instead of wxNullBitmap for wxBitmapComboBoxes.
* Updated wxWidgets.cmake
* OSX specific: Discard BitmapComboBox overrides
+ some code cleaning

src/slic3r/GUI/PhysicalPrinterDialog.hpp

@@ -48,8 +48,7 @@ public:
     void                SuppressDelete();
     void                AllowDelete();
 
-    void                msw_rescale();
-    void                on_sys_color_changed() {};
+    void                on_sys_color_changed();
 };
 
 
@@ -98,7 +97,7 @@ public:
     void        DeletePreset(PresetForPrinter* preset_for_printer);
 protected:
     void on_dpi_changed(const wxRect& suggested_rect) override;
-    void on_sys_color_changed() override {};
+    void on_sys_color_changed() override;
 
     bool had_all_mk3;
 };