(* val color_single : igraph -> Temp.temp * colorlist -> colorlist
* color_single graph (temp, regs) => takes an interference graph, the temp to be colored, and the
* already-colored nodes, colors the temp, and adds it to the list
* this is a helper function for the foldr in colorize
*)
(* val color_single : igraph -> Temp.temp * colorlist -> colorlist
* color_single graph (temp, regs) => takes an interference graph, the temp to be colored, and the
* already-colored nodes, colors the temp, and adds it to the list
* this is a helper function for the foldr in colorize
*)