title: sbt creates multiple scala source directories
body: <p>I am trying to use sbt with IntelliJ Idea. When sbt 0.13.8 refreshes the project, it creates two scala source directories under src/main -> 'scala' and 'scala-2.11'</p>
  
  <p>My scala version is 2.11.6</p>
  
  <p>If I change sbt version to 0.13.5, the refresh creates only one directory -> src/main/scala.</p>
  
  <p>Why could 0.13.8 be creating two directories?</p>