Lit update (#9247)

Lit cigarettes now count as flame sources.
Changed the isflamesource proc from a general proc to an obj/item proc. It is tidier and will be easier to add future flame sources this way.
Removed some hardcoded flame stuff (Such as igniting rags and paper), which depending on an item being a type instead of just being something that could produce a flame. They now check to see if an item counts as a flame source.
Found leftover clown BS while updating paper burning code and killed it off.

code/modules/makeshift/makeshift_reagents.dm

@@ -138,7 +138,7 @@
 	if(!istype(W, /obj/item/reagent_containers/food/snacks) && W.is_open_container())
 		trans_item(W, user)
 		return
-	if(isflamesource(W))
+	if(W.isFlameSource())
 		heat_item(W, user)
 		return
 	if(istype(W) && W.force >= 5 && !has_edge(W) && LAZYLEN(contents - analyzer))
@@ -243,7 +243,7 @@
 		transfer_out = !transfer_out
 		to_chat(user, span("notice", "You [transfer_out ? "open" : "close"] the spigot on the keg, ready to [transfer_out ? "remove" : "add"] reagents."))
 		return
-	if(isflamesource(W) && istype(welder))
+	if(W.isFlameSource() && istype(welder))
 		to_chat(user, span("notice", "You light \the [src] and begin the distillation process."))
 		addtimer(CALLBACK(src, .proc/distill), 60 SECONDS)
 		src.icon_state = "distillery-active"