1.1.3 release

New in this release:

• Added EventStream.feedTo(WritableValue) method.
• Added accumulate(...) operators.
• Added toStateStream() method to the state machine builder.
• Added Subscription.multi(ObservableSet, T -> Subscription) method to dynamically subscribe to elements of an observable set.
• Added a version of merge that merges all event streams in an observable set.
• Added more convenient methods on tuples, Either and EitherEventStream.
• Added EventStream.test(Predicate) operator.
• Added Try type.