board loading messages

During the start-up of a pad we show a loading message with hints. We have adapted /opt/etherpad-lite/node_modules/ep_loading_message/loading_message.js.

var messages = [
  "Tip 1 <br> Use Control key and S to mark a revision <br> Benutze Control-S um eine bestimmte Version zu markieren",
  "Tip 2 <br> Boards are automatically saved in real time <br> Boards werden immer sofort gespeichert",
  "Tip 3 <br> The timeslider is a great way to see previous states of a board <br> Schau dir frühere Version des Boards an",
  "Tip 4 <br><p>If your board does not load try Ctrl-Shift-R to wipe the cache </p><br><p> Mit Ctrl-Shift-R das neueste Layout laden</p>",
  "Tip 5 <br> Paste or upload an image <br> Bild hochladen oder einfügen um es anzuzeigen",
  "Tip 6 <br> BOARD.net is brought to you by fairkom and the etherpad community",
  "Tip 7 <br> BOARD.net is ideal for wish lists, meeting notes, or cheat sheets",
  "Tip 8 <br>Undo: Ctrl-Z, Redo: Ctrl-Y",
  "Tip 9 <br> Get more fair web apps at fairapps.net and consider a donation."
];

A message is being loaded randomly.