Start to work for supporting scala native objects by using msgpack-scala.

Signed-off-by: Tsuyoshi Ozawa <ozawa.tsuyoshi@gmail.com>
Fixed to serialize one events as an array

Signed-off-by: Tsuyoshi Ozawa <ozawa.tsuyoshi@gmail.com>
Added test for basic collections.

Signed-off-by: Tsuyoshi Ozawa <ozawa.tsuyoshi@gmail.com>