SCHEMA-465. Make region splits inclusive to allow for pre-splitting to include all hash prefix values

 - KijiRowKeySplitter now uses the inclusive version of Bytes.split().

issue: https://jira.kiji.org/browse/SCHEMA-465
review: https://review.kiji.org/r/778
contributed-by: alexandre.normand (Alexandre Normand, alexandre.normand@gmail.com)