Shavasana

• Adds materialize() operator for RxBlocking's BlockingObservable. #1383
• Adds first operator to ObservableType.
• Deprecates UIBindingObserver in favor of Binder. #1411
• Adds another specialization of SharedSequence called Signal.
• Refactors DelegateProxy to be type safe.
• Changes nested SharedSequence strategy to use inner sharing strategy for result.

Anomalies

• Call controlTextDidChange(…) as an optional method. #1406
• Fixed issue with NSControl.rx.value regarding multiple observers. #1399
• Removes useless extensions from PrimitiveSequence. #1248