Display a progress bar and allow Esc option.
──────────────────────────────────────────────────────────────────────────────

 Syntax

         GT_Progress(<nCounter>,<lSetup>, ;
             <lAllowEsc>,<nMax>) -> lContinue

 Arguments:

       <nCounter> is the value to base the bar on.
       <lSetup> Initialise !
       <lAllowEsc> Can User Press Esc ?
       <nMax> Max value to close on.

 Returns:

       lContinue

 Description:

       Display a progress bar and allow Esc option.

 Examples:

       // Setup allowing Esc
       GT_Progress(NIL,.T.,.T.,LASTREC())

       // Use it
       DO WHILE GT_Progress(RECNO())
           Update()
       ENDDO

 Source: GT_PROGR.PRG

 Author:  Martin Bryant