-add saveLength to SaveRestore

-undo split of Restore from SaveRestore
-add some dynamic memory management to memory-class

src/knx/ip_parameter_object.cpp

@@ -320,4 +320,9 @@ uint8_t IpParameterObject::propertyCount()
 PropertyDescription* IpParameterObject::propertyDescriptions()
 {
     return _propertyDescriptions;
-}
+}
+
+uint16_t IpParameterObject::saveSize()
+{
+    return 51;
+}