flink

[FLINK-5344] Fixed the dockerized doc build, which has been broken for a while. Fixed the -p option. Reverted the main Gemfile back to ruby 1.9 to make the build bot happy, and created a new Gemfile in ruby2/Gemfile to keep the incremental build option available.

[FLINK-2821] use custom Akka build to listen on all interfaces

[maven] properly attach the CEP Scala source code

[FLINK-5350] don't overwrite an existing JAAS config

[FLINK-5091] cleanup unused Mesos configuration entries