Changed way substitute tools are handled.

Now all tools have chance of success. Proper ones have 100.
If tool has less than 100 chance of success, it can fail the step.

code/modules/surgery/bones.dm

@@ -4,9 +4,10 @@
 //////////////////////////////////////////////////////////////////
 
 /datum/surgery_step/glue_bone
-	priority = 2
-	required_tool = /obj/item/weapon/bonegel
-	allowed_tools = list(/obj/item/weapon/screwdriver)
+	allowed_tools = list(
+	/obj/item/weapon/bonegel = 100,	\
+	/obj/item/weapon/screwdriver = 75
+	)
 	can_infect = 1
 	blood_level = 1
 
@@ -37,8 +38,10 @@
 		"\red Your hand slips, smearing [tool] in the incision in [target]'s [affected.display_name]!")
 
 /datum/surgery_step/set_bone
-	required_tool = /obj/item/weapon/bonesetter
-	allowed_tools = list(/obj/item/weapon/wrench)
+	allowed_tools = list(
+	/obj/item/weapon/bonesetter = 100,	\
+	/obj/item/weapon/wrench = 75		\
+	)
 
 	min_duration = 60
 	max_duration = 70
@@ -72,8 +75,10 @@
 		affected.createwound(BRUISE, 5)
 
 /datum/surgery_step/mend_skull
-	required_tool = /obj/item/weapon/bonesetter
-	allowed_tools = list(/obj/item/weapon/wrench)
+	allowed_tools = list(
+	/obj/item/weapon/bonesetter = 100,	\
+	/obj/item/weapon/wrench = 75		\
+	)
 
 	min_duration = 60
 	max_duration = 70
@@ -102,8 +107,10 @@
 		h.disfigured = 1
 
 /datum/surgery_step/finish_bone
-	required_tool = /obj/item/weapon/bonegel
-	allowed_tools = list(/obj/item/weapon/screwdriver)
+	allowed_tools = list(
+	/obj/item/weapon/bonegel = 100,	\
+	/obj/item/weapon/screwdriver = 75
+	)
 	can_infect = 1
 	blood_level = 1