Make it easier to apply the required Browserify transform

package/package.json

@@ -1,6 +1,6 @@
 {
   "name": "ol",
-  "version": "4.0.1-beta.1",
+  "version": "4.0.1-beta.2",
   "description": "OpenLayers as ES2015 modules",
   "main": "index.js",
   "module": "index.js",
@@ -10,5 +10,15 @@
     "pixelworks": "1.1.0",
     "rbush": "2.0.1",
     "vector-tile": "1.3.0"
+  },
+  "browserify": {
+    "transform": [
+      [
+        "babelify",
+        {
+          "plugins": ["transform-es2015-modules-commonjs"]
+        }
+      ]
+    ]
   }
 }