2.1.6 release preparation

[akarnokd]

Version 2.1.6 - October 27, 2017 (Maven)

API changes

• Pull 5649: Add Observable.concatMapCompletable().
• Pull 5655: Add Flowable.limit() to limit both item count and request amount.

Documentation changes

• Pull 5648: Improve package JavaDoc of io.reactivex and io.reactivex.observers.
• Pull 5647: Fix subscribeWith documentation examples.
• Pull 5651: Update Observable.just(2..10) and switchOnNextDelayError marbles.
• Pull 5668: Fix a misleading documentation of Observable.singleElement().
• Pull 5680: More Observable marble fixes.

Bugfixes

• Pull 5669: Fix PublishProcessor cancel/emission overflow bug.
• Pull 5677: Make parallel() a fusion-async-boundary.

Other

• Pull 5652: Inline disposability in Observable.concatMap(Completable).
• Pull 5653: Upgrade testng to get method names to show up in gradle console when skipping, and in testng html output.
• Pull 5661: Improve Flowable.timeout().

[akarnokd]

Closing via 2.1.6.