Makes the arrivals shuttle more robust (#2565)

It's harder to mess with the shuttle and after failing to return so many times it boots people off. It also connects the airlocks to distro and gives it a backup canister.

code/game/objects/effects/landmarks.dm

@@ -25,6 +25,10 @@
 			latejoin += loc
 			delete_me = 1
 			return
+		if("KickoffLocation")
+			kickoffsloc += loc
+			delete_me = 1
+			return
 		if("JoinLateGateway")
 			latejoin_gateway += loc
 			delete_me = 1