InfoAgent; improve monitoring to better handle duplicate monitor requests

InfoAgent monitoring has been improved to better handle duplicate monitor requests, i.e. for the same vehicle.

Previously it was possible to get orphaned monitors, where finPOWER Connect thinks it is monitoring a vehicle but it is not being monitored in InfoAgent.

Consider this example:

A vehicle is monitored under Security Statement A. It is then also monitored under Security Statement B. In finPOWER Connect both Security Statements are recorded as being monitored. However, in InfoAgent it is only recorded as being monitored under Reference B - monitoring the same vehicle simply updates the Reference.

Note, Reference is the Security Statement Id.

If the monitor is stopped in finPOWER Connect for Security Statement A (or B), the other Security Statement B (or A) will still be recorded as monitored. In InfoAgent the vehicle is no longer monitored. Therefore there is an orphaned monitor in finPOWER Connect which is not desirable.

The change is that InfoAgent will now fail if the same vehicle is added as a monitor with a different Reference.

This prevents you registering the same vehicle for multiple Security Statements.