refs #413 Make all value class methods non-virtual.

toCVariant() and convertFromCVariant() are now deprecated,
use CVariant::from() and CVariant::to() instead.

src/blackmisc/iconlist.h

@@ -39,7 +39,7 @@ namespace BlackMisc
         CIcon findByIndex(CIcons::IconIndex index) const;
 
         //! \copydoc CValueObject::asQVariant
-        virtual QVariant toQVariant() const override { return QVariant::fromValue(*this); }
+        QVariant toQVariant() const { return QVariant::fromValue(*this); }
 
         //! Register metadata of unit and quantity
         static void registerMetadata();