SetConsoleEcho (HighLine::SystemExtensions)

    # File lib/highline/system_extensions.rb, line 52
          def SetConsoleEcho( console_handle, on )
            mode = GetConsoleMode(console_handle)

            # toggle the console echo bit
            if on
                mode |=  ENABLE_ECHO_INPUT
            else
                mode &= ~ENABLE_ECHO_INPUT
            end

            ok = SetConsoleMode(console_handle, mode)
          end