provide hints for running CryptPad

www/common/sframe-boot2.js

@@ -36,5 +36,14 @@ define([
     // This test is completed in common-interface.js
     Test(function (t) { Test.__ASYNC_BLOCKER__ = t; });
 
+    window.onerror = function (e) {
+        if (/requirejs\.org/.test(e)) {
+            console.log();
+            console.error("Require.js threw a Script Error. This probably means you're missing a dependency for CryptPad.\nIt is recommended that the admin of this server runs `bower install && bower update` to get the latest code, then modify their cache version.\nBest of luck,\nThe CryptPad Developers");
+            return void console.log();
+        }
+        throw e;
+    };
+
     require([document.querySelector('script[data-bootload]').getAttribute('data-bootload')]);
 });