ssh.transport logger messages are no longer sent to the log window,
because we can't wrap them in wx.CallAfter, so they can cause GUI
threading problems, which have been observed on Mac OS X.

Also, reduced the sleep time between repeated checks for whether
TurboVNC version number check has completed from 1 second to
0.5 seconds.  See: while self.turboVncVersionNumber=="0.0":