fix commonJS and plain version deps

knockout-sortable.js

@@ -6,10 +6,11 @@
     } else if (typeof require === "function" && typeof exports === "object" && typeof module === "object") {
         // CommonJS module
         var ko = require("knockout");
-        factory(ko);
+        var Sortable = require('./Sortable');
+        factory(ko, Sortable);
     } else {
         // No module loader (plain <script> tag) - put directly in global namespace
-        factory(window.ko);
+        factory(window.ko, window.Sortable);
     }
 })(function (ko, Sortable) {
     "use strict";