Fix gcc9 compiler warnings

See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58407

src/blackgui/eventfilter.h

@@ -31,7 +31,7 @@ namespace BlackGui
 
     protected:
         //! Filter
-        bool eventFilter(QObject *object, QEvent *event);
+        virtual bool eventFilter(QObject *object, QEvent *event) override;
 
     private:
         QString m_illegalChars;

src/blackmisc/orderable.h

@@ -55,9 +55,6 @@ namespace BlackMisc
         //! Constructor
         IOrderable(int order);
 
-        //! Constructor
-        IOrderable(const IOrderable &orderable) : IOrderable(orderable.m_order) {}
-
         //! \copydoc BlackMisc::Mixin::Index::propertyByIndex
         CVariant propertyByIndex(const CPropertyIndex &index) const;