kiji-express: EXP-344. Express needs integration tests

 - Plumbing for integration tests using AbstractKijiIntegrationTest.
 - Simple integration test.

issue: https://jira.kiji.org/browse/EXP-344
review: https://review.kiji.org/r/1434
commit: https://github.com/kijiproject/kiji-express/commit/55e97abb2eaec48b09366fa5cdccd553055c434f