function getDevices()

Returns a json array list of devices

$fulldevicelist = $zwa->getDevices();

    {
        "creationTime": 1478995567,
        "creatorId": 13,
        "deviceType": "toggleButton",
        "h": 557861323,
        "hasHistory": true,
        "id": "LightScene_13",
        "location": 1,
        "metrics": {
            "level": "on",
            "icon": "",
            "title": "Scene Morning"
        },
        "permanently_hidden": false,
        "probeType": "",
        "tags": [],
        "visibility": true,
        "updateTime": 1479284400
    },
    {
        "creationTime": 1478981288,
        "creatorId": 1,
        "deviceType": "switchMultilevel",
        "h": 1107079067,
        "hasHistory": true,
        "id": "ZWayVDev_zway_3-0-38",
        "location": 1,
        "metrics": {
            "icon": "multilevel",
            "title": "Bedside Lamp",
            "level": 0
        },
        "permanently_hidden": false,
        "probeType": "multilevel",
        "tags": [],
        "visibility": true,
        "updateTime": 1479286803
    },
    {
        "creationTime": 1478980773,
        "creatorId": 1,
        "deviceType": "sensorMultilevel",
        "h": 1303283136,
        "hasHistory": true,
        "id": "ZWayVDev_zway_2-0-49-1",
        "location": 1,
        "metrics": {
            "probeTitle": "Temperature",
            "scaleTitle": "°C",
            "level": 20.5,
            "icon": "temperature",
            "title": "Temperature"
        },
        "permanently_hidden": false,
        "probeType": "temperature",
        "tags": [],
        "visibility": true,
        "updateTime": 1479287686
    }