Updated (custom) Candy distribution; fix chatroom

* Fix chatroom to use the calculated course room, rather than the
  testing-only 'dev' room.
* Install new version of candy.min.js compiled with an Aria tag for the
  input box (see also:
  https://github.com/jrbl/candy/tree/input-accessibility-improvement)

Co-authored-by: Giulio Gratta <caeser2164@gmail.com>
Co-authored-by: Nate Hardison <natehardison@gmail.com>

lms/djangoapps/jabber/templates/chat.html

@@ -21,8 +21,8 @@
     <script type="text/javascript">
       $(document).ready(function() {
         Candy.init("${bosh_url}", {
-          //core: { debug: true, autojoin: ["${course_room}"] },
-          core: { debug: true, autojoin: ["dev@conference.jabber.class.stanford.edu"] },
+          core: { debug: true, autojoin: ["${course_room}"] },
+          //core: { debug: true, autojoin: ["dev@conference.jabber.class.stanford.edu"] },
           view: { resources: "${static.url('candy_res/')}"}
         });