remove speculative code from copygb2

[edwardhartnett]

In copygb2 we have:

              call errmsg('Option -A Ignored...Not yet implemented.')
              LAB = 1      ! default value, since -A option not yet implemented.
              AB = -1.E30  ! default value, since -A option not yet implemented.
           ELSEIF(CARG(L:L) .EQ. 'B') THEN
              IF(L .EQ. LARG) THEN
                 L = 0
                 CALL GETARG(IARG, CARG)
                 LARG = LEN_TRIM(CARG)
                 IARG = IARG + 1
              ENDIF
              LCGB = LARG - L
              CGB = CARG(L + 1:LARG)
              L=LARG
              call errmsg('Option -B Ignored...Not yet implemented.')
              LCGB = 1     ! default value, since -B option not yet implemented.
              CGB = ' '    ! default value, since -B option not yet implemented.
           ELSEIF(CARG(L:L) .EQ. 'b') THEN
              IF(L .EQ. LARG) THEN
                 L = 0
                 CALL GETARG(IARG, CARG)
                 LARG = LEN_TRIM(CARG)
                 IARG = IARG + 1
              ENDIF
              LCXB = LARG - L
              CXB = CARG(L + 1:LARG)
              L = LARG
              call errmsg('Option -b Ignored...Not yet implemented.')
              LCXB = 1     ! default value, since -B option not yet implemented.
              CXB = ' '    ! default value, since -B option not yet implemented.

So these unimplemented options need to be removed.