Moving "implementation detail" classes out of public API
Move blocking operators to BlockingObservable

- see https://github.com/Netflix/RxJava/issues/270 for background
Deprecating 'toObservable' duplications of 'from' methods
Migrating from 'toObservable' to 'from' and using toBlockingObservable() where needed
Make unit test more deterministic
README on internal nature of rx.operators package
Merge pull request #272 from benjchristensen/BlockingObservable

BlockingObservable