new io scheme

new io scheme

SCCS-vsn: usr.bin/window/wwinit.c 3.14
SCCS-vsn: usr.bin/window/wwopen.c 3.15
SCCS-vsn: usr.bin/window/ww.h 3.25
SCCS-vsn: usr.bin/window/cmd.c 3.20
SCCS-vsn: usr.bin/window/cmd1.c 3.20
SCCS-vsn: usr.bin/window/wwgets.c 3.3
SCCS-vsn: usr.bin/window/cmd2.c 3.22
SCCS-vsn: usr.bin/window/defs.h 3.8
SCCS-vsn: usr.bin/window/cmd4.c 3.7
SCCS-vsn: usr.bin/window/cmd5.c 3.9
SCCS-vsn: usr.bin/window/:ww 1.7
SCCS-vsn: usr.bin/window/cmd6.c 3.7
SCCS-vsn: usr.bin/window/wwpty.c 3.6
SCCS-vsn: usr.bin/window/mloop.c 3.2
SCCS-vsn: usr.bin/window/wwiomux.c 3.7
SCCS-vsn: usr.bin/window/win.c 3.2