common: avoid c cast by delegating to cast operator explicitly

alib2common/src/object/Object.h

@@ -214,7 +214,7 @@ public:
 	 * \returns string representation of the wrapped object
 	 */
 	explicit operator std::string ( ) const {
-		return ( std::string ) * m_data;
+		return m_data->operator std::string ( );
 	}
 	/**