Fix memory leak in bounded ReplaySubject due to retaining the node index
indefinitely once the Subscriber caught up.
Remove Unused Scheduler.parallelism

Before hitting 1.0 removing this API as it is not used.
Merge pull request #1882 from benjchristensen/scheduler-parallelism

Remove Unused Scheduler.parallelism
Fix Scan/Reduce/Collect Factory Ambiguity

This puts the seed factory on `collect` and removes it from `scan` and `reduce` due to ambiguity.
See https://github.com/ReactiveX/RxJava/pull/1883 and https://github.com/ReactiveX/RxJava/issues/1881
Merge pull request #1884 from benjchristensen/mutable-collect-scan-reduce

Fix Scan/Reduce/Collect Factory Ambiguity
Merge pull request #1866 from akarnokd/ReplaySubjectMemoryLeakFix

Fix memory leak in bounded ReplaySubject due to retaining the node index