Since adding:
"org.specs2" %% "specs2" % "2.4.15" % "test" withSources() withJavadoc(),
To my build file I get
[warn] Note: Unresolved dependencies path:
[warn] org.scalaz.stream:scalaz-stream_2.10:0.5a
[warn] +- org.specs2:specs2_2.10:2.4.15
...
[error] (*:update) sbt.ResolveException: unresolved dependency: org.scalaz.stream#scalaz-stream_2.10;0.5a: not found