Begin d3 v4 update

modules/renderer/tile_layer.js

@@ -1,13 +1,15 @@
-import { prefixCSSProperty } from '../util/index';
+import * as d3 from 'd3';
+import { d3geoTile } from '../../js/lib/d3.geo.tile';
+import { prefixCSSProperty, functor } from '../util/index';
 export function TileLayer(context) {
     var tileSize = 256,
-        tile = d3.geo.tile(),
+        tile = d3geoTile(),
         projection,
         cache = {},
         tileOrigin,
         z,
         transformProp = prefixCSSProperty('Transform'),
-        source = d3.functor('');
+        source = functor('');
 
 
     // blacklist overlay tiles around Null Island..