Cross build 2.12.x

[enzief]

Needed for downstreams to use 2.12.x Please advice on things to change and version bump.

[kailuowang]

Thanks! Build faired. We probably need to update travis.yml as well. I will take a closer look after holidays.

[kailuowang]

looks like some of the dependencies need to be bumped particularly gatling library and sbt plugins. Unfortunately, my schedule is very tight at the moment. @enzief Would you be interested in taking a look? Basically, we need to make sure that the following works on Scala 2.12.

  sbt "stressFrontend/run false"
  sbt stress

[coveralls]

Coverage decreased (-0.2%) to 85.763% when pulling 1e561dd72f72cf886fd9c0c5dd9f1df3b7a23f80 on enzief:mdrm/scala212 into 451d3a6bfc6e57be4f8db2e7f6bf290f451fa07f on iheartradio:0.5.x.

[enzief]

@kailuowang sure, I'll see what I can do.