Merge pull request #933 from dotty-staging/revert-sbt

Fix sbt build.

Author: odersky

project/build.properties

@@ -1 +1 @@
-sbt.version=0.13.9
+sbt.version=0.13.5

project/plugins.sbt

@@ -8,4 +8,5 @@ addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "4.0.0")
 // See https://github.com/scalastyle/scalastyle/issues/156#issuecomment-137229733
 addSbtPlugin("org.scalastyle" %% "scalastyle-sbt-plugin" % "0.7.0" excludeAll(
   ExclusionRule(organization = "com.danieltrinh")))
+
 libraryDependencies += "org.scalariform" %% "scalariform" % "0.1.7"