Update nodejs demos

I've taken the liberty of trying to update the nodejs demos in this repo to work with the new google-api-nodejs-client. I haven't actually tested the changes so if someone could give this a second look & perhaps test it, that'd be awesome.

Plus general feedback is always welcome. Maybe we want to scrap this altogether and create a better demo?
There was minimal discussion around transitioning it to the new library. Since release, no external developer has mentioned its disappearance (which doesn't mean it wasn't useful) and I always thought it was more of an unpredictable feature if defaults were changed midway through using the library or if certain api calls didn't use the parameter at all. I've filed an issue for bringing the feature back: https://github.com/google/google-api-nodejs-client/issues/278