BUG: Libs/Core - Added missing virtual destructor to ctkAbstract*FactoryItem classes

Libs/Core/ctkAbstractFactory.h

@@ -39,6 +39,7 @@ class ctkAbstractFactoryItem
 {
 public:
   explicit ctkAbstractFactoryItem(const QString& key);
+  virtual ~ctkAbstractFactoryItem(){}
   
   virtual QString loadErrorString()const;
   virtual bool load() = 0;

Libs/Core/ctkAbstractLibraryFactory.h

@@ -39,6 +39,7 @@ protected:
 
 public:
   explicit ctkFactoryLibraryItem(const QString& key, const QString& path);
+  virtual ~ctkFactoryLibraryItem(){}
   virtual bool load();
   QString path()const;
   virtual QString loadErrorString()const;

Libs/Core/ctkAbstractObjectFactory.h

@@ -46,6 +46,7 @@ protected:
   typedef BaseClassType *(*InstantiateObjectFunc)();
 public:
   explicit ctkFactoryObjectItem(const QString& key);
+  virtual ~ctkFactoryObjectItem(){}
   virtual bool load();
 protected:
   virtual BaseClassType* instanciator();

Libs/Core/ctkAbstractPluginFactory.h

@@ -34,6 +34,7 @@ class ctkFactoryPluginItem : public ctkAbstractFactoryItem<BaseClassType>
 {
 public:
   explicit ctkFactoryPluginItem(const QString& key, const QString& path);
+  virtual ~ctkFactoryPluginItem(){}
   virtual bool load();
   QString path()const;
   virtual QString loadErrorString()const;