Refactor Subscriber to support backpressure in lift
Refactor Subscriber to support backpressure in lift

zhongdj/RxScala,jbripley/RxScala,hermanbanken/RxScala,ReactiveX/RxScala,jbripley/RxScala,zjrstar/RxScala,hermanbanken/RxScala,joohnnie/RxScala,TracyLu/RxScala