Re-enable Java 8 on Travis (#466)
Re-enable Java 8 on Travis (#466)

chrysalag/lenskit,martinlaz/lenskit,kluver/lenskit,kluver/lenskit,blankazucenalg/lenskit,vijayvani/Lenskit,kluver/lenskit,martinlaz/lenskit,kluver/lenskit,vaibhav345/lenskit,linjunleo/lenskit,binweiwu/lenskit,binweiwu/lenskit,amaliujia/lenskit,amaliujia/lenskit,blankazucenalg/lenskit,aglne/lenskit,tajinder-txstate/lenskit,vaibhav345/lenskit,vijayvani/Lenskit,chrysalag/lenskit,vaibhav345/lenskit,tajinder-txstate/lenskit,kluver/lenskit,tajinder-txstate/lenskit,linjunleo/lenskit,vaibhav345/lenskit,aglne/lenskit,tajinder-txstate/lenskit