Upgrade to Scala 2.11

087ac309831a59e896e22ef10249eced31bd228e make `Unit` a case object

4d3f02cb8358738b5639714b8a6bc007b2162556 answer why we need type annotation around `EP`

61550e9d5d6bb4eb4f6fd493acf3d6c1ef0266d7 make LIGD compile with scalac 2.11.1 by moving type annotations in a pattern one level up