Update .travis.yml
Use JRuby 1.7.9
Use kafka v0.8.0 jars

From GitHub and in a separate branch for now.
Broker#zk_string was removed in v0.8.0
Move json require to spec_helper
Don’t discard zookeeper and kafka console output
Sleep until zookeeper and kafka responds
Emit contents of all the log-files after startup
Run only in jruby (no jruby-head)
Log also after script