0.2.0

Apply patches from RxJava 2 since April 21:

• Pull 5449: Remove the @NonNull annotation from Function.
• Pull 5447: Remove @NonNull annotation in Consumer method parameter.
• Pull 5444: Fix wording in Async and Publish processors javadoc.
• Pull 5441: Fix periodic scheduler purging config not honored.
• Pull 5440: Fix concat to report isDisposed consistently with termination.
• Pull 5436: Gradle to use less memory, missed an export command.
• Pull 5434: Fix time bounded ReplaySubject getValue() inconsistency with getValues() on old items.
• Pull 5432: Fix/clarify the Observable class' javadoc.
• Pull 5427: Fix buffer(time, maxSize) duplicating buffers on time-size race.
• Pull 5422: More eager cancellation in flatMapX.
• Pull 5421: Attempt to fix a few time-sensitive tests.
• Pull 5419: Fix periodic scheduling with negative period causing IAE.
• Pull 5415: Fix doOnNext failure not triggering doOnError when fused.
• Commit 84d333e0: Fix a small typo in Single.delay.
• Commit 4d8f008c: Add missing 'the' to the changed sentences of 5413.
• Pull 5413: Add empty source clauses to javadocs of combineLatest operators.
• Pull 5409: Corrected Single.delay documentation.
• Pull 5406: Fix javadoc for Observable.reduce() and Observable.reduceWith().
• Pull 5407: DefaultSubscriber javadoc sample fix.
• Pull 5405: DefaultObserver javadoc example fix.
• Pull 5403: Fix documentation of Single.doAfterTerminate.
• Pull 5386: Add subscribeOn overload to avoid same-pool deadlock with create.
• Pull 5391: Changed minimum value of rx2.buffer-size to 1.
• Pull 5379: Add missing null checks on values returned by user functions.
• Pull 5383: Fixed Javadoc for SingleFlatMapIterableObservable. (already fixed from an earlier commit).
• Pull 5378: Make SingleMap not allow map function return null.
• Pull 5367: Make sure interval+trampoline can be stopped.
• Commit 0b0355e3: Replace Action1 with Consumer in docs.
• Pull 5354: Fix typo in error message.
• Pull 5351: Update some marbles of Observable.
• Pull 5347: Fix Javadoc of FunctionX.
• Pull 5344: Add tryOnError to create/XEmitter API.
• Pull 5343: Fix Javadoc for Maybe.toSingle.
• Pull 5324: Mark VolatileSizeArrayList as RandomAccess list.
• Pull 5310: Improve coverage of some classes (no functional changes).
• Pull 5309: Fix Javadoc of Flowable.toObservable.
• Pull 5307: Apply promotions for v2.1