FUNCTION SL_DOWNROW()

  Short:
  ------
  SL_DOWNROW() Move the printer cursor up/down by # rows,
  relative to position

  Returns:
  --------
  cCode => control string to send to the printer

  Syntax:
  -------
  SL_DOWNROW(nRows)

  Description:
  ------------
  Move print head down <nRows>. A negative number means
  move UP.

  Actual end position will depend on both LINES PER
  INCH settings.

  Examples:
  ---------
   ?SL_DOWNROW(10)

   ??"Hello world"

   ?SL_DOWNROW(-1)    // moves to prior row

   ?SL_OVERCOL(-11)   // and back to starting column

   ??"Attention:"

  Notes:
  -------
  Does not send anything to the printer - instead
  returns a control string that you send to the printer. String can be
  sent with ? or ?? or  QOUT() or QQOUT().

  For HP and compatible(PCL) Laserjet printers.

  Source:
  -------
  S_HPLAS.PRG