kiji-express: EXP-368. Create KijiOutput.Builder

issue: https://jira.kiji.org/browse/EXP-368
review: https://review.kiji.org/r/1506
commit: https://github.com/kijiproject/kiji-express/commit/6107fd17399b24d8e85804c5d61cf0d229e33a57
kiji-modeling: Move files to parent project, instead of sub module.

review: https://review.kiji.org/r/1512
commit: https://github.com/kijiproject/kiji-modeling/commit/c9b896af8b1629f2bdcbb822c9dd2c8430b3da49