Scala subsystem for Repeat.
For simplicity, all subsystems are versioned using the same version number as the main system (in Java) for every release.
Play json 2.4.6 https://mvnrepository.com/artifact/com.typesafe.play/play-json_2.11/2.4.6 Scala Logging 3.4.0 https://github.com/typesafehub/scala-logging