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/structures/window.dm

@@ -24,7 +24,7 @@
 	var/silicate = 0 // number of units of silicate
 	var/fulltile = FALSE // Set to true on full-tile variants.
 
-/obj/structure/window/examine(mob/user)
+/obj/structure/window/examine(mob/user, distance, infix, suffix)
 	. = ..()
 
 	if(health == maxhealth)