Update index.html

sandbox/index.html

@@ -28,6 +28,7 @@
 
     <link href="index.css" rel="stylesheet" />
     <script src="https://code.jquery.com/pep/0.4.2/pep.min.js"></script>
+    <script src="https://playground.babylonjs.com/js/libs/split.js"></script>
 
     <script src="https://preview.babylonjs.com/cannon.js"></script>
     <script src="https://preview.babylonjs.com/Oimo.js"></script>