Use layer id to disamgibuate layers

[caseycesari]

If there are layers within the same map service that have the same name, allow developers to specify the layer id in the config to disambiguate these layers.

Update the documentation accordingly.

Testing

• Update layers.json with the following:

[
    {
        "name": "Grenada",
        "server": {
            "type": "ags",
            "layerType": "dynamic",
            "url": "http://dev.services2.coastalresilience.org/arcgis/rest/services/GSVG",
            "name": "GSVG"
        },
        "includeLayers": [
            {
                "id": 1,
                "name": "Inundation Scenarios",
                "includeAllLayers": true
            },
            {
                "name": "Ecological",
                "id": 9,
                "includeAllLayers": true
            },
            {
                "id": 19,
                "name": "Social and Economic",
                "includeLayers": [
                    {
                        "id": 20,
                        "name": "Critical Infrastructure",
                        "includeAllLayers": true
                    }
                ]
            }
        ]
    },
    {
        "name": "St Vincent and the Grenadines",
        "server": {
            "type": "ags",
            "layerType": "dynamic",
            "url": "http://dev.services2.coastalresilience.org/arcgis/rest/services/GSVG",
            "name": "GSVG"
        },
        "includeLayers": [
            {
                "id": 115,
                "name": "Inundation Scenarios",
                "includeAllLayers": true
            },
            {
                "id": 123,
                "name": "Ecological",
                "includeAllLayers": true
            },
            {
                "id": 133,
                "name": "Social and Economic",
                "includeLayers": [
                    {
                        "id": 134,
                        "name": "Critical Infrastructure",
                        "includeAllLayers": true
                    }
                ]
            }
        ]
    }
]

• Toggle the layers, and verify that the duplicate layers in each group are in fact turning on and off different layers.

Connects to #51

[kdeloach]

+1 Great fix!

[caseycesari]

Thanks!