UnitTests demonstrating bugs
Make unsubscribe idempotent.
Make unsubscribe idempotent.
BugFix: Handling of Terminal State for Behavior/Publish Subjects

- They were not correctly emitting onCompleted when new Observers subscribed after the Subject was terminated.
- Added same logic that already existed on AsyncSubject
Merge pull request #525 from benjchristensen/bugfix-subjects

BugFix: Handling of Terminal State for Behavior/Publish Subjects