scalastyle 0.5.0 (new formula)

Scalastyle is a style checker for Scala. They have a CLI interface and there
have been requests to make it available as a Homebrew formula:
  https://github.com/scalastyle/scalastyle-batch/issues/1

Here is such a formula. :)
Installed to `etc`. I had it inline before but it's 9k and made the code hard to follow.