FUNCTION POPEX()

  Short:
  ------
  POPEX() Pops up an achoice for a certain filespec

  Returns:
  --------
  <cFileName> => file name or "" for none

  Syntax:
  -------
  POPEX(cSkel,[cTitle])

  Description:
  ------------
  Pops up a picklist for all files matching the
  skeleton given as <cSkel>. i.e. "*.dbf"

  If a path is passed, the path is returned as part of
  the filename.

  Optional title string [cTitle] - displays at top of
  box

  Examples:
  ---------
   cOpendbf := POPEX("*.DBF")
       // => will return DBF name

   opendbf = POPEX("C:\FILES\*.DBF")
       // => will return "C:\FILES\" plus DBF name

  Source:
  -------
  S_POPEX.PRG