reactivex.io documentation needs to reference v5+

The docs on reactivex.io e.g. http://reactivex.io/documentation/operators/repeat.html still reference the v4 implementation API.

I'm not immediately sure how these docs are generated and more importantly, kept in sync with our real docs. I imagine @mattpodwysocki knows, so hopefully he can help lead the way.

If it's currently just manual process of updating their repo, I'm initially inclined to just remove them and/or link to our docs instead. It's not ideal, but I think it's better than having to continuously be told our docs on reactivex.io are out of date or not as good as our real docs (if they ever are actually good...)