title: Spark 2.0 missing spark implicits
body: <p>Using Spark 2.0, Im seeing that it is possible to turn a dataframe of row's into a dataframe of case classes. When I try to do so, Im greeted with a message stating to import <code>spark.implicits._</code>. The issue that I have is that Intellij isn't recognizing that as a valid import statement, Im wondering if that has moved and the message hasn't been updated, or if I don't have the correct packages in my build settings, here is my <code>build.sbt</code> </p>
  
  <pre><code>libraryDependencies ++= Seq(
    "org.mongodb.spark" % "mongo-spark-connector_2.11" % "2.0.0-rc0",
    "org.apache.spark" % "spark-core_2.11" % "2.0.0",
    "org.apache.spark" % "spark-sql_2.11" % "2.0.0"
  )
  </code></pre>