to test chunked result, add some functionalities

* [Scala] add enumChunks() method which is retrieve ChunkedResult as Enumerator

* [Scala] add headChunks() method which is retrieve head of ChunckedResult as Option[Array[Byte]]

* [Scala] add getChunks() method which is retrive whole ChunkedResult as List[Array[Byte]]

* [Java] add headOfChunks() method which is retrieve head of ChunckedResult as Array[Byte]

* [Java] add allOfChunks() method which is retrieve head of ChunckedResult as java.util.List[Array[Byte]]

* [Scala] and also add specs test of enumChunks, headChunks, getChunks.