Make classes in ol/ available as named exports from ol

src/ol/ImageTile.js

@@ -1,7 +1,7 @@
 /**
  * @module ol/ImageTile
  */
-import {inherits} from './index.js';
+import {inherits} from './util.js';
 import Tile from './Tile.js';
 import TileState from './TileState.js';
 import {createCanvasContext2D} from './dom.js';