Provide a pluggable Browserify transform about regenerator

[zanona]

I am not sure if this is something that should be held within regenerator but at the moment it seems it's not possible to handle errors emitted through a regenerator transformation through browserify.

So:

browserify(src)
   .transform(require('regenerator'))
   .bundle(function (err, bundle) {
       if (err) { return handleError(err); }
       handleBundle(bundle);
   });

where handleError never gets triggered and the application crashes beforehand because apparently regenerator is throwing an Error instead of emitting through this.emit('error', new Error())

more on how to achieve this:
https://github.com/substack/node-browserify/blob/071642ad9cbb44cb530d43edfac17c5077a9442c/test/tr_error.js#L11-L13