All mechs have a melee attack now, the force of non combat mechs is 5.

Changing the mech melee attack code to be more object oriented. Creating mech_melee_attack() proc for atom and overidden in its children.
Mechs can now hit windoors with their melee attack. (they can still open them by bumping)

code/game/objects/structures.dm

@@ -1,11 +1,11 @@
-obj/structure
+/obj/structure
 	icon = 'icons/obj/structures.dmi'
 
-obj/structure/blob_act()
+/obj/structure/blob_act()
 	if(prob(50))
 		qdel(src)
 
-obj/structure/ex_act(severity)
+/obj/structure/ex_act(severity)
 	switch(severity)
 		if(1.0)
 			qdel(src)
@@ -17,7 +17,14 @@ obj/structure/ex_act(severity)
 		if(3.0)
 			return
 
-obj/structure/Destroy()
+/obj/structure/Destroy()
 	if(opacity)
 		UpdateAffectingLights()
-	..()
+	..()
+
+/obj/structure/mech_melee_attack(obj/mecha/M)
+	if(M.damtype == "brute")
+		M.occupant_message("<span class='danger'>You hit [src].</span>")
+		visible_message("<span class='danger'>[src] has been hit by [M.name].</span>")
+		return 1
+	return 0