Add scala-refactoring to the community build.

I wasn't able to run the script locally (tons of EXTRACTION FAILED). I also just updated the build.sbt in scala-refactoring to build with Scala 2.11, but this isn't in a release yet so I target that specific commit.
In other words, I'm suspecting you might actually get scala-library that sbt uses itself. Forking tests might also help verify that hypothesis.