SVGHMI: add support for "reference" and "frame" rectangles to spread-out ovelapping elements.
When HMI become complicated, designer needs to spread-out ovelapping elements
in order to unclutter drawing and facilitate maintenance.
<?xml version='1.0' encoding='utf-8'?>
<BACnetServerNode xmlns:xsd="http://www.w3.org/2001/XMLSchema" UDP_Port_Number="47808" BACnet_Device_ID="3" BACnet_Communication_Control_Password=" " BACnet_Device_Location="Beremiz lab" Network_Interface="virbr0"/>