Add setting for linkgraph times to be in non daylength scaled days.

Savegame format change for link graph jobs.
Change link graph scheduler to support more than one operation
per day, on _date_fract ticks other than SPAWN_JOIN_TICK.

src/saveload/extended_ver_sl.cpp

@@ -67,6 +67,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_EXTRA_LARGE_MAP,        XSCF_NULL,              0,                                    1, "extra_large_map",       NULL, NULL, NULL        },
 	{ XSLFI_REVERSE_AT_WAYPOINT,    XSCF_NULL,              1,                                    1, "reverse_at_waypoint",   NULL, NULL, NULL        },
 	{ XSLFI_VEH_LIFETIME_PROFIT,    XSCF_NULL,              1,                                    1, "veh_lifetime_profit",   NULL, NULL, NULL        },
+	{ XSLFI_LINKGRAPH_DAY_SCALE,    XSCF_NULL,              1,                                    1, "linkgraph_day_scale",   NULL, NULL, NULL        },
 	{ XSLFI_NULL, XSCF_NULL, 0, 0, NULL, NULL, NULL, NULL },// This is the end marker
 };