using hashes to perform comparisons between blackmisc value objects stored inside of QVariant

refs #81

src/blackmisc/valueobject.cpp

@@ -60,6 +60,16 @@ namespace BlackMisc
         return vo;
     }
 
+    /*
+     * Compare
+     */
+    int CValueObject::compare(const QVariant & /** qv **/) const
+    {
+        // not all classes have to implement this
+        qFatal("Property by index as string not implemented");
+        return -1; // avoid compiler warning
+    }
+
     /*
      * from DBus
      */