Replace http://reactivex.io/rxjs/ docs

[Dorus]

The docs on http://reactivex.io/rxjs/ currently contain the docs generated from https://github.com/ReactiveX/rxjs and are not updated for years, wasting hours of development time because of mistakes.

The rxjs-docs docs should replace these docs.

[ladyleet]

@Dorus that is our goal! :) lots of work ahead though!