refactor buckling to be more generic

Buckling procs and vars have been moved down to /obj.
Behaviour is mostly the same, but you can buckle cuffed people to
 pipes and they will automatically unbuckle if the cuffs are removed.

Signed-off-by: Mloc-Argent <colmohici@gmail.com>

code/datums/spells/area_teleport.dm

@@ -47,7 +47,7 @@
 			return
 
 		if(target && target.buckled)
-			target.buckled.unbuckle()
+			target.buckled.unbuckle_mob()
 
 		var/list/tempL = L
 		var/attempt = null

code/datums/spells/ethereal_jaunt.dm

@@ -20,7 +20,7 @@
 
 			if(target.buckled)
 				var/obj/structure/stool/bed/buckled_to = target.buckled.
-				buckled_to.unbuckle()
+				buckled_to.unbuckle_mob()
 
 			var/mobloc = get_turf(target.loc)
 			var/obj/effect/dummy/spell_jaunt/holder = new /obj/effect/dummy/spell_jaunt( mobloc )