Scala travis check

@OlegIlyenko Is this okay?
@schleichardt you can't define multiple languages on travis. But each worker has already a default set of runtimes (http://docs.travis-ci.com/user/ci-environment/#Runtimes) and java machines have probably some extra tools installed (so you don't need to install anything for like python or scala or node). 
So if `language: java` covers everything ok (but no need to define multiple languages), otherwise we should simply split each language into their own repo (like https://github.com/sphereio/sphere-hello-api-nodejs) so you can specify workers for your language (with multiple versions).