Converts some istype's to use helpers (#3224)

Converts various istype's to use helpers. Mainly:
Cable
Wrench
Screwdriver
Multitool
Crowbar
Wirecutter

And makes the helpers defines.

code/modules/modular_computers/hardware/ai_slot.dm

@@ -28,7 +28,7 @@
 		stored_card = W
 		W.forceMove(src)
 		update_power_usage()
-	if(istype(W, /obj/item/weapon/screwdriver))
+	if(isscrewdriver(W))
 		user << "You manually remove \the [stored_card] from \the [src]."
 		stored_card.forceMove(get_turf(src))
 		stored_card = null

code/modules/modular_computers/hardware/hardware.dm

@@ -15,7 +15,7 @@
 
 /obj/item/weapon/computer_hardware/attackby(var/obj/item/W as obj, var/mob/living/user as mob)
 	// Multitool. Runs diagnostics
-	if(istype(W, /obj/item/device/multitool))
+	if(ismultitool(W))
 		to_chat(user, "***** DIAGNOSTICS REPORT *****")
 		diagnostics(user)
 		to_chat(user, "******************************")
@@ -31,7 +31,7 @@
 			damage = 0
 		return 1
 	// Cable coil. Works as repair method, but will probably require multiple applications and more cable.
-	if(istype(S, /obj/item/stack/cable_coil))
+	if(iscoil(S))
 		if(!damage)
 			to_chat(user, "\The [src] doesn't seem to require repairs.")
 			return 1