kiji-scoring: SCORE-148. Add a CLI to run ScoreFunctions in batch

issue: https://jira.kiji.org/browse/SCORE-148
review: https://review.kiji.org/r/1566
commit: https://github.com/kijiproject/kiji-scoring/commit/b9f147f5f5683a36d9c6e2e90d45dffefddd4ba3