Netflix/RxJava — pull request #1422 by benjchristensen (2014-07-10 22:04:12+00:00)
Title: Concurrency Fixes for RxRingBuffer & Merge

Possible fix for #1420

I was unable to exactly reproduce the issue, but was able to create a possibly related one. This fixes it.
It also simplifies the logic and code somewhat, at a possible small performance cost for these:

```
r.o.OperatorMergePerf.merge1SyncStreamOfN 1000 thrpt 5 59407.716 2073.945 ops/s
r.o.OperatorMergePerf.merge1SyncStreamOfN 1000000 thrpt 5 66.557 2.693 ops/s
r.o.OperatorMergePerf.mergeNSyncStreamsOfN 1000 thrpt 5 59.293 5.046 ops/s
```