Added TomTom layers (#329)

README.md

@@ -65,6 +65,16 @@ In order to use ArcGIS maps, you must [register](https://developers.arcgis.com/e
 
 [Available Esri layers](http://leaflet-extras.github.io/leaflet-providers/preview/#filter=Esri)
 
+### TomTom
+
+In order to use TomTom layers, you must [register](https://developer.tomtom.com/user/register). Once registered, you can create an `apikey` which you have to pass to `L.tileLayer.provider` in the options:
+
+```Javascript
+L.tileLayer.provider('TomTom', {
+    apikey: '<insert your API key here>'
+}).addTo(map);
+```
+
 ### Geoportail France
 
 In order to use Geoportail France resources, you need to obtain an [api key]( http://professionnels.ign.fr/ign/contrats/) that allows you to access the [resources](https://geoservices.ign.fr/documentation/donnees-ressources-wmts.html#ressources-servies-en-wmts-en-projection-web-mercator) you need. Pass this api key and the ID of the resource to display to `L.tileLayer.provider` in the options: 

leaflet-providers.js

@@ -332,6 +332,24 @@
 				}
 			}
 		},
+		TomTom: {
+			url: 'https://{s}.api.tomtom.com/map/1/tile/{variant}/{style}/{z}/{x}/{y}.{ext}?key={apikey}',
+			options: {
+				variant: 'basic',
+				maxZoom: 22,
+				attribution:
+					'<a href="https://tomtom.com" target="_blank">&copy;  1992 - ' + new Date().getFullYear() + ' TomTom.</a> ',
+				subdomains: 'abcd',
+				style: 'main',
+				ext: 'png',
+				apikey: '<insert your API key here>',
+			},
+			variants: {
+				Basic: 'basic',
+				Hybrid: 'hybrid',
+				Labels: 'labels'
+			}
+		},
 		Esri: {
 			url: 'https://server.arcgisonline.com/ArcGIS/rest/services/{variant}/MapServer/tile/{z}/{y}/{x}',
 			options: {