adding several marble diagrams

several new marble diagrams for previously undiagrammed methods
Merge pull request #279 from DavidMGross/master

Adding marble diagrams
Diagrams and some new docs for Observable subclasses

Some marble or marblish diagrams and a bit of new documentation for the
BlockingObservable and ConnectableObservable subclasses.
Merge pull request #280 from DavidMGross/master

Diagrams and some new javadoc content for Observable subclasses