Fixed deadlock in Subjects + OperatorCache.
Merge branch 'SubjectDeadlockFix320' of github.com:akarnokd/RxJava into pull-972

Conflicts:
	rxjava-core/src/main/java/rx/operators/OperatorCache.java

Updated OperatorCache to use `unsafeSubscribe` to fix merge conflicts.
Simplify Subscription/Observer State
Remove Redundant Action1 Observer Collection Argument

Since the collection is being returned we don't want to also inject it as an argument, so I migrated to Action0 from Action1 as per discussion at https://github.com/Netflix/RxJava/pull/972#issuecomment-38189145
Merge pull request #1040 from benjchristensen/pull-972

Merge and Cleanup of #972