IntelliJ-Idea support, better SBT project setup

This adds support for IntelliJ idea.

As far as I could see, there was no support for IntelliJ. This adds the ability to create projects and import them.

It also adds the JUnit runner, needed in IntelliJ.

Additionally, it adds the ScalaTest library via SBT. Projects generated through SBT will be able to link to the dependency.