Added spawnpoint datum, moved existing latejoin spawn to datum setup.

code/global.dm

@@ -125,7 +125,12 @@ var/airtunnel_bottom = 72 // default
 var/list/monkeystart = list()
 var/list/wizardstart = list()
 var/list/newplayer_start = list()
+
+//Spawnpoints.
 var/list/latejoin = list()
+var/list/latejoin_gateway = list()
+var/list/latejoin_cryo = list()
+
 var/list/prisonwarp = list()	//prisoners go to these
 var/list/holdingfacility = list()	//captured people go here
 var/list/xeno_spawn = list()//Aliens spawn at these.