Temperature tweaks (#1277)

Fixes thermostats not working when set to 0 celsius.
Clamps instead of discards thermostat inputs that are out of range. So you can just type in 99999 and it'll set the highest valid value (usually 40c)
Tiny optimisation to remove a duplicate check in thermoregulation code

code/modules/reagents/Chemistry-Machinery.dm

@@ -70,7 +70,11 @@
 		B.loc = src
 		user << "You add the pill bottle into the dispenser slot!"
 		src.updateUsrDialog()
-	return
+	else if(istype(B, /obj/item/weapon/wrench))
+		anchored = !anchored
+		user << "You [anchored ? "attach" : "detach"] the [src] [anchored ? "to" : "from"] the ground"
+		playsound(src.loc, 'sound/items/Ratchet.ogg', 75, 1)
+
 
 /obj/machinery/chem_master/Topic(href, href_list)
 	if(..())