beremiz

Arbitrary variables added to JsonTable subscription are now passed as 'extra' field in json query. As an example added JsonTable filtering in tests/svghmi
<?xml version='1.0' encoding='utf-8'?>
<ModbusServerNode xmlns:xsd="http://www.w3.org/2001/XMLSchema" Local_Port_Number="1502" Local_IP_Address="127.0.0.1"/>