Refactor - use `rvagg/nan` v1.1.0

So, this seems to be pretty close, but not quite there. I'm still getting 2 build errors on my machine.

I'm having trouble specifically with figuring out how to implement the `writeObject()` and and `readObject()` functions using `nan` API.

If one of the nan gurus could take a look that would be very much appreciated :beers: 
/cc @rvagg @kkoopa @bnoordhuis