Fixes #176

Removes most of the examples and replaces them with one TCK-verified, strict-adhering to the spec, documented asynchronous `AsyncIterablePublisher`.
This should address #176 for now, and more examples, preferably an `AsyncSubscriber` would be great.

@reactive-streams/contributors Yay or nay? Weigh in here before the 19th (this is example code so does not affect spec or interfaces)
I'd put a comment here that we found this to be required, otherwise the test would not be detected (even if listed explicitly in `testng.yaml`), so noone does the "seems not needed, boom delete" mistake