Add webpack bundle for external dependencies

src/bundle.js

@@ -0,0 +1,9 @@
+/**
+ * require.js module definitions bundled by webpack
+ */
+// Use define from require.js not webpack's define
+var _define = window.define;
+
+var jstree = require("jstree");
+require("jstree/dist/themes/default/style.css");
+_define("jstree", ["jQuery"], function() { return jstree; });