Mostly replaced by prompt_popup for more customization.
Usage: prompt_user <-pause MESSAGE>
  -pause MESSAGE: Pops a window prompting the user with MESSAGE.
                  Program does not return until user responds.
                  note: if MESSAGE is '-', it is read from stdin
  -timeout TT: Timeout in seconds of prompt message. Default answer
               is returned if TT seconds elapse without user
  -to TT: Same as -timeout TT