Update loading message (shows until server says it's okay)

Small change to make the loading message load up by default client-side until the server says its okay (either sends loaded sketch or finds no sketch in db and says it's okay).

Can we get this updated to http://draw.etherpad.org please? It would be more helpful in debugging plus we get the new color picker! :)

Do you want me to just update it in the future or do you prefer to do the pushing to the server?