diff -r e8daf3ff497d -r b25c02bd6b11 build.sbt
--- a/build.sbt	Thu Nov 19 18:36:56 2015 +0100
+++ b/build.sbt	Thu Nov 19 19:08:18 2015 +0100
@@ -6,6 +6,8 @@
 
 scalaVersion := "2.11.7"
 
+scalacOptions += "-feature"
+
 resolvers += "spray repo" at "http://repo.spray.io"
 
 val sprayVer = "1.3.2"