de-tkhack the child processes

later sub-Perls were loading Tk when they should not,
  possibly bringing the Xserver down?
  certainly making it harder to read the log output
wrap XmuClientWindow's XGetWindowProperty in Tk_CreateErrorHandler

to fix a rare but persistent BadWindow crash
  seen on (Lenny, Lucid) Gnome desktop
  often after closing another application
extra LangDebug for ClientMessage and XmuClientWindow