add rainbow wires

sim/simulation.lua

@@ -184,7 +184,10 @@ function Simulation.connectwireat(sim, wire, x, y, z)
 	for k, obj in pairs(objs) do
 		if obj ~= wire and obj.group ~= nil then
 			if is_wire(obj) then -- wire
-				if Wire.getlayer(obj) == Wire.getlayer(wire) then -- same layer
+				local layer1 = Wire.getlayer(wire)
+				local layer2 = Wire.getlayer(obj)
+				--if they are on the same real layer, or exactly one is rainbow but not both, then connect
+				if ((layer1==layer2) or (layer1==-1 and layer2~=-1) or (layer1~=-1 and layer2==-1)) and (not (layer1==-1 and layer2==-1)) then
 					Group.addwire(obj.group, wire)
 				end
 			else -- port