title: Set custom response headers in Play 2.1 (scala)
body: <p>I'm aware of <a href="https://stackoverflow.com/questions/8199490/setting-http-headers-in-play-2-0-scala">Setting HTTP headers in Play 2.0 (scala)?</a></p>
  
  <p>But how do I set a custom response header like <code>X-Hello-World</code> in the play framework?</p>