examine signature changed to include distance

- distance is INFINITE, 0, or a positive integer based on get_dist() between
the examiner and examinee's turfs when they are on the same Z. When the
examiner is dead or a ghost, distance is always 0.
- also updates /examine( implementations to use it!
- adds w_class_to_name proc for reusing "It is a X item." examine behavior.

code/game/objects/items/stacks/marker_beacons.dm

@@ -41,7 +41,7 @@ var/global/list/marker_beacon_colors = list(
 	. = ..()
 	update_icon()
 
-/obj/item/stack/marker_beacon/examine(mob/user)
+/obj/item/stack/marker_beacon/examine(mob/user, distance, infix, suffix)
 	. = ..()
 	. += "<span class='notice'>Use in-hand to place a [singular_name].</span>"
 	. += "<span class='notice'>Alt-click to select a color. Current color is [picked_color].</span>"
@@ -97,7 +97,7 @@ var/global/list/marker_beacon_colors = list(
 		picked_color = mapped_in_color
 	update_icon()
 
-/obj/structure/marker_beacon/examine(mob/user)
+/obj/structure/marker_beacon/examine(mob/user, distance, infix, suffix)
 	. = ..()
 	if(!perma)
 		. += "<span class='notice'>Alt-click to select a color. Current color is [picked_color].</span>"

code/game/objects/items/stacks/stack.dm

@@ -56,10 +56,9 @@
 			icon_state = "[initial(icon_state)]_3"
 		item_state = initial(icon_state)
 
-/obj/item/stack/examine(mob/user)
+/obj/item/stack/examine(mob/user, distance, infix, suffix)
 	. = ..()
-
-	if(Adjacent(user))
+	if(distance < 2)
 		if(!uses_charge)
 			. += "There [src.amount == 1? "is" : "are"] [src.amount] [src.singular_name]\s in the stack."
 		else
@@ -76,7 +75,7 @@
 
 /obj/item/stack/tgui_data(mob/user, datum/tgui/ui, datum/tgui_state/state)
 	var/list/data = ..()
-	
+
 	data["amount"] = get_amount()
 
 	return data
@@ -120,7 +119,7 @@
 			if(get_amount() < 1)
 				qdel(src)
 				return
-			
+
 			var/datum/stack_recipe/R = locate(params["ref"])
 			if(!is_valid_recipe(R, recipes)) //href exploit protection
 				return FALSE