*** Example Homebridge config.json "accessories" configuration ***

        {
            "accessory": "mqttthing",
            "type": "securitySystem",
            "name": "Security System",
            "url": "http://127.0.0.1:1883",
            "topics":
            {
                "getCurrentState":    "vista/Get/SystemStatus",
                "getTargetState":     "vista/Get/SystemStatus",
                "setTargetState":     "vista/Set/Cmd"
            },
            "targetStateValues": ["S", "A", "N", "D"]
        },
        {
            "accessory": "mqttthing",
            "type": "smokeSensor",
            "name": "Smoke Alarm",
            "url": "http://127.0.0.1:1883",
            "topics":
            {
                "getSmokeDetected": "vista/Get/FIRE"
            },
            "integerValue": "true"
        },
        {
            "accessory": "mqttthing",
            "type": "contactSensor",
            "name": "Zone 1",
            "url": "http://127.0.0.1:1883",
            "topics":
            {
                "getContactSensorState": "vista/Get/Zone/1"
            },
            "integerValue": "true"
        },
        {
            "accessory": "mqttthing",
            "type": "contactSensor",
            "name": "Zone 2",
            "url": "http://127.0.0.1:1883",
            "topics":
            {
                "getContactSensorState": "vista/Get/Zone/2"
            },
            "integerValue": "true"
        }