Scalatest 2.2.0

This pull request is on top of [cd742d7](https://github.com/hanxue/sbt-intellij-skeleton/commit/cd742d7228e7ee6f39de1462fdc2cf4880ef19e5) . Either merge this pull request and ignore earlier, or better to cherry-pick only commit  [cb09939](https://github.com/hanxue/sbt-intellij-skeleton/commit/cb09939a11e0c66f010013299ab767d14070a8ac)