ATT()

  Short:
  ------
  ATT() Colors a section of the screen, leaving the text intact

  Returns:
  --------
  <cUnder> => Underlying screen before change

  Syntax:
  -------
  Att(nTop,nLeft,nBottom,nRight,nColorAttribute)

  Description:
  ------------
  <nTop>             - top row
  <nLeft>            - left col
  <nBottom>          - bottom row
  <nRight>           - right column
  <nColorAttribute>  - attribute to set area  (numeric color )

  Saves and returns the underlying screen at <ntop,nLeft,nBottom,nRight>

  Examples:
  ---------
   ATT(5,5,10,10,79)   // sets 5,5,10,10 to +W/R

  Notes:
  ------
  This was a C file previously

  Source:
  -------
  S_ATT.PRG