Improved merge perf tests
progress ...
Functional merge ... 1 performance issue left

volatile touched in emitWithoutQueue is hurting performance.
Some unit tests failing elsewhere
Not handling backpressure requirements on downstream merge ... put merge().observeOn() unit test to show this.
fix bugs related to object pool and RxRingBuffer

... all tests passing exception 1 related to merge that is known and not implemented yet.
... one known performance issue in RxRingBuffer.emitWithoutQueue