Fixed one of the issues in the BuildManager men...

Fixed one of the issues in the BuildManager mentioned in scala#2590, where
adding a missing reference wasn't causing compilation of the dependent
files. Still, the solution to the whole ticket requires some changes to
the scala plugin itself.

Author: Hubert Plociniczak

src/compiler/scala/tools/nsc/interactive/RefinedBuildManager.scala

@@ -197,6 +197,8 @@ class RefinedBuildManager(val settings: Settings) extends Changes with BuildMana
               invalidate(file, "it references changed class", change)
             case Changed(Definition(name)) if (refs(name)) =>
               invalidate(file, "it references changed definition", change)
+            case Added(Definition(name)) if (refs(name)) =>
+              invalidate(file, "it references added definition", change)
             case _ => ()
           }
         }