Declare var types
Detangle IDEA model implementation from the public cross-version api, and fix IdeaContentRoot.getGeneratedSourceDirectories() and getGeneratedTestDirectories() so that they actually return something.
Javadocs and @Incubating for stuff added to the IDEA tooling model.
Changed UnderDevelopmentGradleDistribution.executer() to return whatever executer we're using to run the tests, rather than always forking.