Add idiomatic toXXX methods to RxScala
Avoid the cast in toSet and toBuffer
Merge pull request #1375 from zsxwing/rxscala-toXXX

RxScala: Add idiomatic toXXX methods
More work on #1322 (missing javadocs)
Merge branch 'master' of https://github.com/Netflix/RxJava into docs