twitter/zipkin — pull request #346 by suchang (2014-02-26 20:10:44+00:00)
Title: Summingbird: serializer, injections and configs

This PR provides additional components needed for summingbird jobs:
1) serialization for span and a monoid used by summingbird sumByKey()
2) injection scheme for span
3) config changes: the scala version is bumped to 2.9.3.