window-port updates

Remove start_screen() and end_screen() from the
Window-port interface.

They were only ever used by tty, and there was a comment
carried to several window-ports about how they "really
should go away. They are tty-specific"

term_start_screen() and term_end_screen() are part of
terminal/NO_TERMS supporting routines now.

win/chain/wc_chainin.c

@@ -59,9 +59,6 @@ short chainin_set_font_name(winid, char *);
 char *chainin_get_color_string(void);
 #endif
 
-    /* other defs that really should go away (they're tty specific) */
-void chainin_start_screen(void);
-void chainin_end_screen(void);
 void chainin_outrip(winid, int, time_t);
 void chainin_preference_update(const char *);
 char *chainin_getmsghistory(boolean);
@@ -489,19 +486,6 @@ trace_get_color_string(void)
 
 #endif
 
-/* other defs that really should go away (they're tty specific) */
-void
-chainin_start_screen(void)
-{
-    (*cibase->nprocs->win_start_screen)(cibase->ndata);
-}
-
-void
-chainin_end_screen(void)
-{
-    (*cibase->nprocs->win_end_screen)(cibase->ndata);
-}
-
 void
 chainin_outrip(
     winid tmpwin,
@@ -629,8 +613,6 @@ struct window_procs chainin_procs = {
     chainin_get_color_string,
 #endif
 
-    chainin_start_screen, chainin_end_screen,
-
     chainin_outrip, chainin_preference_update, chainin_getmsghistory,
     chainin_putmsghistory,
     chainin_status_init, chainin_status_finish, chainin_status_enablefield,