Fix virtual dtor warnings

Fix warnings about classes with virtual methods but non-virtual dtors by
adding a virtual dtor to ctkWidgetInstanciator, and removing a
gratuitous 'virtual' from ctkVTKPropertyWidgetPrivate.

Libs/Visualization/VTK/Widgets/ctkVTKPropertyWidget.cpp

@@ -38,7 +38,7 @@ protected:
 public:
   ctkVTKPropertyWidgetPrivate(ctkVTKPropertyWidget& object);
 
-  virtual void setupUi(QWidget *widget);
+  void setupUi(QWidget *widget);
 
   vtkSmartPointer<vtkProperty> Property;
 };

Libs/Widgets/ctkSimpleLayoutManager.h

@@ -31,6 +31,7 @@ class ctkSimpleLayoutManagerPrivate;
 /// \ingroup Widgets
 struct ctkWidgetInstanciator
 {
+  virtual ~ctkWidgetInstanciator() {}
   virtual void beginSetupLayout(){}
   virtual void endSetupLayout(){}
   virtual QWidget* createWidget() = 0;