NAN 1.5 WIP

This branch will become NAN 1.5.
Added Asyncworker #207 and new NanNew #210. Needs more testing with actual addons.
Now split into many files. Seems to work so far. Good news for nauv.h
But that happens on a new line all by itself, so it cannot exceed 80 columns. Now I did the other, uglier thing and split it in two