Unmarshal received this when marshalling closures

[71104]

The following program:

let http = process.mainModule.require "http" in

let server = http.createServer fn request, response ->
  response.end.apply {"Oh hai!"} in

server.listen 8080

fails in Node v4.4.5.

The reason is that the native function generated when marshalling Lambda closures doesn't add the received this to the context.

This bug will probably be obsoleted by #84, which will require reimplementing tha closure marshaller from scratch, but it still needs to be reported.