- Added self.sshTunnelExceptionOccurred = True to additional except
  block within createTunnel() method, so user doesn't have to
  wait for tunnel attempt to time out if an execption occurs.
- Added code to hide progress dialog and return cursor to default,
  before displaying "Can't create SSH tunnel" dialog.
- Removed KeyboardInterrupt exception in createTunnel method,
   because users should cancel using the Cancel button on the
   progress dialog, not using Control-C.
- Reduced some sleep times from 1 to 0.1