update nan to work with io.js 2.x.x

[markzrt]

hi, the problem is..... you know :

...return v8::Signature::New(v8::Isolate::GetCurrent(), receiver, argc, argv);

please :D

[eljefedelrodeodeljefe]

@peterbraden is someone actively working on a port to [email protected]. Also maybe porting to OpenCV 3.0 #273 might be related. For NAN there currently is no migration guide and known issues.
Both are intertwined, yet it's very worth the shot. I could send in a PR after this week, if no-one is working on it.

[peterbraden]

I'd love a PR :) AFAIK nobody is working on it yet.

[danschultzer]

Nan has been upgraded to v2.0.9 in #309. Latest release of node-opencv also works with OpenCV 3.0.