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/modules/detectivework/tools/evidencebag.dm

@@ -90,7 +90,7 @@
 		icon_state = "evidenceobj"
 	return
 
-/obj/item/evidencebag/examine(mob/user)
+/obj/item/evidencebag/examine(mob/user, distance, infix, suffix)
 	. = ..()
 	if(stored_item)
 		user.examinate(stored_item)