Move buckling to /atom/movable, can now buckle to mobs if adminbooze

Also changed:
 - Comment clarifying what buckle_lying = -1 means
 - Changes direction of lying on operating tables, somehow missed it

code/modules/mob/living/carbon/carbon.dm

@@ -309,6 +309,10 @@ var/list/ventcrawl_machinery = list(/obj/machinery/atmospherics/unary/vent_pump,
 		src << "You can't vent crawl while you're stunned!"
 		return
 
+	if(buckled_mob)
+		src << "You can't vent crawl with [buckled_mob] on you!"
+		return
+
 	var/obj/machinery/atmospherics/unary/vent_found
 
 	if(clicked_on)

code/modules/mob/living/carbon/human/human.dm

@@ -185,7 +185,7 @@
 			return
 
 		//BubbleWrap: people in handcuffs are always switched around as if they were on 'help' intent to prevent a person being pulled from being seperated from their puller
-		if((tmob.a_intent == I_HELP || tmob.restrained()) && (a_intent == I_HELP || src.restrained()) && tmob.canmove && !tmob.buckled && canmove) // mutual brohugs all around!
+		if((tmob.a_intent == I_HELP || tmob.restrained()) && (a_intent == I_HELP || restrained()) && tmob.canmove && canmove && !tmob.buckled && !tmob.buckled_mob) // mutual brohugs all around!
 			var/turf/oldloc = loc
 			loc = tmob.loc
 			tmob.loc = oldloc

code/modules/mob/living/living.dm

@@ -317,7 +317,7 @@
 			C.reagents.addiction_list.Cut()
 	hud_updateflag |= 1 << HEALTH_HUD
 	hud_updateflag |= 1 << STATUS_HUD
-	
+
 /mob/living/proc/update_revive() // handles revival through other means than cloning or adminbus (defib, IPC repair)
 	stat = CONSCIOUS
 	dead_mob_list -= src
@@ -406,7 +406,7 @@
 	return
 
 /mob/living/Move(atom/newloc, direct)
-	if (buckled && buckled.loc != newloc)
+	if (buckled && buckled.loc != newloc) //not updating position
 		if (!buckled.anchored)
 			return buckled.Move(newloc, direct)
 		else

code/modules/mob/mob.dm

@@ -1019,9 +1019,6 @@ var/list/slot_equipment_priority = list( \
 /mob/proc/facedir(var/ndir)
 	if(!canface())	return 0
 	dir = ndir
-	if(buckled && buckled.movable)
-		buckled.dir = ndir
-		buckled.handle_rotation()
 	client.move_delay += movement_delay()
 	return 1
 
@@ -1398,3 +1395,30 @@ mob/proc/yank_out_object()
 
 /mob/proc/handle_ventcrawl()
 	return // Only living mobs can ventcrawl
+
+//You can buckle on mobs if you're next to them since most are dense
+/mob/buckle_mob(mob/living/M)
+	if(M.buckled)
+		return 0
+	var/turf/T = get_turf(src)
+	if(M.loc != T)
+		var/old_density = density
+		density = 0
+		var/can_step = step_towards(M, T)
+		density = old_density
+		if(!can_step)
+			return 0
+	return ..()
+
+//Default buckling shift visual for mobs
+/mob/post_buckle_mob(mob/living/M)
+	if(M == buckled_mob) //post buckling
+		M.pixel_y = initial(M.pixel_y) + 9
+		if(M.layer < layer)
+			M.layer = layer + 0.1
+	else //post unbuckling
+		M.layer = initial(M.layer)
+		M.pixel_y = initial(M.pixel_y)
+
+/mob/proc/can_unbuckle(mob/user)
+	return 1

code/modules/mob/mob_defines.dm

@@ -118,7 +118,7 @@
 	var/m_int = null//Living
 	var/m_intent = "run"//Living
 	var/lastKnownIP = null
-	var/obj/structure/stool/bed/buckled = null//Living
+	var/atom/movable/buckled = null//Living
 	var/obj/item/l_hand = null//Living
 	var/obj/item/r_hand = null//Living
 	var/obj/item/weapon/back = null//Human/Monkey

code/modules/mob/mob_movement.dm

@@ -1,16 +1,19 @@
-/mob/CanPass(atom/movable/mover, turf/target, height=0, air_group=0)
-	if(air_group || (height==0)) return 1
-
-	if(istype(mover) && mover.checkpass(PASSMOB))
+/mob/CanPass(atom/movable/mover, turf/target, height=0)
+	if(height==0)
+		return 1
+	if(istype(mover, /obj/item/projectile) || mover.throwing)
+		return (!density || lying)
+	if(mover.checkpass(PASSMOB))
+		return 1
+	if(buckled == mover)
 		return 1
 	if(ismob(mover))
 		var/mob/moving_mob = mover
 		if ((other_mobs && moving_mob.other_mobs))
 			return 1
-		return (!mover.density || !density || lying)
-	else
-		return (!mover.density || !density || lying)
-	return
+		if (mover == buckled_mob)
+			return 1
+	return (!mover.density || !density || lying)
 
 
 /client/North()