Remove references to now-removed akka sub projects.

    [info] [error] These subprojects were not found: "akka-channels-tests", "akka-sbt-plugin", "akka-sample-cluster", "akka-channels-experimental".
    [info] [error] Use 'last' for the full log.
Merge pull request #2 from retronym/topic/akka-subs

Remove references to now-removed akka sub projects.