restore languages-datepicker manual test

tests/languages-datepicker.html

@@ -6,6 +6,7 @@
 <link href='../dist/fullcalendar.css' rel='stylesheet' />
 <link href='../dist/fullcalendar.print.css' rel='stylesheet' media='print' />
 <script src='../lib/jquery/dist/jquery.js'></script>
+<script src='../lib/jquery-ui/jquery-ui.js'></script>
 <script src='../lib/moment/moment.js'></script>
 <script src='../dist/fullcalendar.js'></script>
 <script src='../dist/lang-all.js'></script>