DirTree()

         Create an array with structure of a disk

    Syntax:

         DirTree( cMask, cDir ) -> aArray

         cMask : Format the directories must fulfill to be searched.
         cDir  : Begining directory.

    Description:

         Returns an array with specified directories order from father to
         child.

    Return:

         An array with directories.

    Example:

         Window ( 4, 0, 22, 29, "Directory C:\", "+-+|+-+| ", .T. )
         aChoice ( 5, 2, 21, 27, DirTree ( "\*.*", "C:\" ), .T. )