Moved ProcessCallable from AbstractProcessStage to ProcessStageRunner
Removed some unused constants from AbstractProcessStage
Travis now runs "mvn verify" instead of "mvn test"
integration_tests
Merge branch 'travis_fixup' into integration_tests
Merge branch 'integration_tests' into major_api_refactoring

Conflicts:
	test-suite/src/test/java/com/findwise/hydra/TestPipeline.java