2.1.7 release preparations

[akarnokd]

Version 2.1.7 - November 27, 2017 (Maven)

API changes

• Pull 5729: Implement as() operator on the 6 base classes - similar to to() but dedicated functional interface for each base class instead of just Function.

Documentation changes

• Pull 5706: Remove mentions of Main thread from Schedulers.single() JavaDoc.
• Pull 5709: Improve JavaDocs of flatMapSingle and flatMapMaybe.
• Pull 5713: Add BaseTestConsumer values() and errors() thread-safety clarifications.
• Pull 5717: Add period to custom scheduler use sentences in Schedulers.
• Pull 5718: Add a sentence to documentation of take() operator about the thread onComplete may get signaled.
• Pull 5738: Correct JavaDoc for ConnectableFlowable, GroupedFlowable, FlowableAutoConnect.
• Pull 5740: Marbles for Observable all, fromPublisher, zipArray.

Bugfixes

• Pull 5695: Fix Completable.concat to use replace (don't dispose old).
• Pull 5715: Distinguish between sync and async dispose in ScheduledRunnable.
• Pull 5743: Check isDisposed before emitting in SingleFromCallable.

Other

• Pull 5723: Remove duplicate nullity check line in toMap.

[akarnokd]

Closing via 2.1.7.