Include version in JavaScript code

issue11697
review417971003

src/sao.js

@@ -1,6 +1,8 @@
 /* This file is part of Tryton.  The COPYRIGHT file at the top level of
    this repository contains the full copyright notices and license terms. */
-var Sao = {};
+var Sao = {
+    __version__: '6.5.0',
+};
 
 (function() {
     'use strict';