Restore use of SpmcArrayQueue in RxRingBuffer

- Modification of SpmcArrayQueue with fix from https://github.com/JCTools/JCTools/issues/21
- Restore RxRingBuffer to use SpmcArrayQueue
- this reduces object allocation significantly (see pull request for screenshots)
Merge pull request #1526 from benjchristensen/ring-buffer-queue

Restore use of SpmcArrayQueue in RxRingBuffer