xsbt: add Hadoop jars to unmanaged classpath

gistfile1.scala

  lazy val hadoopHomePath =
    Properties.envOrNone("HADOOP_HOME").map { file }.getOrElse(error("please set HADOOP_HOME"))

  lazy val main = Project(groupName, file("."),
    settings = defaultSettings ++ Seq(
      unmanagedClasspath in Compile <<= (unmanagedClasspath in Compile, baseDirectory) map {
        (cp, bd) => cp ++ Attributed.blankSeq(hadoopHomePath ** "*.jar" get)
      }
    )
  )