Adding Login Scanner for MyBook Live

This is a LoginScanner auxiliary module for Western
Digital MyBook Live NAS devices as well as the spec
for testing.
Looking at the code a second time, I think the logic here is that there might not even be a response (in which case reporting res.headers would cause an exception).  I can put logic in there to report the header if the response exists if you would like. Let me know how you would like to handle that.