(weekday, daytime, daytime_range): New; replace kw_parse(). Parsing

is somewhat stricter.
(is_wday_allowed, is_daytime_allowed, is_daytime_nar,
min_to_next_daytime): New.
(demand_update_time, scheduled_update_time, next_scheduled_time,
update_time, gamehours): Use them to replace kw_parse().
(kw_parse): No longer used, remove.

src/server/update.c

@@ -34,7 +34,6 @@
 
 #include "misc.h"
 #include "player.h"
-#include "keyword.h"
 #include "empthread.h"
 #include "prototypes.h"
 #include "optlist.h"
@@ -49,7 +48,6 @@ time_t update_time;
 void
 update_sched(void *unused)
 {
-    s_char *kw;
     int wind;
     time_t now, delta;