* library/managedwin.ith (_ignore_on_save): New protected method.

    * library/managedwin.ith (_ignore_on_save): New protected method.
        * library/managedwin.itb (shutdown): If _ignore_on_save, don't
        save this window to the active window list in the preferences
        file.
        * library/debugwin.ith (DebugWin::_ignore_on_save): Don't save
        this window to preferences active list.
        (DebugWinDOpts::_ignore_on_save): Likewise.
        * library/pluginwin.itcl (_ignore_on_save): Likewise.
        * library/download.ith (_ignore_on_save): Likewise.