2129 patches for twenex (VTS)

[Glenn S. Burke <GSB at MIT-MC>]

STTY1A+15 should be SKIPN VTS20P rather than SKIPE.  This will make
(status tty) return the correct last two values rather than 0.

Instead of
	MOVE 2,TI.ST6(TT)
at OPNT2+22, there should be the sequence
	RTMOD
	HRR 2,TI.ST6(TT)
	IOR 2,[STDTMW]
This will make "the right things" happen when a suspended lisp comes up
on a different terminal (type) from that which it was suspended on.
This has been patched on OZ.  I will update the BBLISP and LISP EXE
files on XX now, as the SS structure there seems to be restored.