Node 0.11.x support

With these changes, node_mdns builds and runs under Node 0.11.14 and nan 1.3 although I cannot say with certainty as amount of testing it received with these changes is too little.
Thanks for the explanation, @kkoopa. I'm still wondering why nan doesn't expose `Integer::NewFromUnsigned` by specializing:

````
NAN_INLINE v8::Local<v8::Integer> NanNew(unsigned int val) {
    return v8::Integer::NewFromUnsigned(val);
  }
````

I mean `NanNew(...)` seems already pretty damn well specialized, overloaded and whatnot. I kinda thought the point was to *bind them all*. `Integer::NewFromUnsigned` just seems to be missing.

However, thanks for the heads up!