[Java] Move build on Travis to Ubuntu 16.04 LTS.
[Java] Move build on Travis to Ubuntu 16.04 LTS.

real-logic/Aeron,galderz/Aeron,mikeb01/Aeron,real-logic/Aeron,mikeb01/Aeron,mikeb01/Aeron,EvilMcJerkface/Aeron,real-logic/Aeron,galderz/Aeron,EvilMcJerkface/Aeron,EvilMcJerkface/Aeron,EvilMcJerkface/Aeron,mikeb01/Aeron,galderz/Aeron,galderz/Aeron,real-logic/Aeron