AsyncWrap minor fixes
Finally getting around to finishing the AsyncWrap
implementation. Here are some mostly minor changes. One specifically is breaking. Instead of needing to set the object field to enable/disable callbacks there are now methods on the async_wrap
import. e.g.
var async_wrap = process.binding('async_wrap');
async_wrap.setupHooks(asyncInit, asyncBefore, asyncAfter);
async_wrap.enable();
// do stuff
async_wrap.disable();
R=@bnoordhuis