NAME: GetDir

     USE: Procedure to return the current directory of a specified drive.
          The directory of the currently logged drive is found by passing
          a value of 0.  The directories of other drives can be found by
          passing the cooresponding values of 1 = A, 2 = B ... n = N.
          Errors are returned through IOResult.

     DEPENDENCY:  None

     SYNTAX:  GetDir(DriveValue : Byte; Var DirString : String);