Run xml tests on Travis using TestRunner

[metteo]

Using test runner app in jts-app. It may require modifications since Travis doesn't support GUI apps.

[metteo]

Using xvfb to start the runner in headless environment. Tests which are working are run as part of the jts-app build, in integration-test phase. The rest from failure/ and robust/ are failing so are run after main build finishes. Test runner may require modification to support sth similar to @test(expected = TopologyException.class)