GitLab CI support

[gyorb]

Gitlab has various ways to show code quality and test result produced by a CI job.

• Code Quality view which requires that the analysis results are in a partial codeclimate json format
• JUnit test reports

Introducing codeclimate json and JUnit xml output format for the commands which are used in CI scripts would make the integration in Gitlab much easier. The sub commands which should be extended are:

• [x] parse codeclimate #2675
• [ ] parse junit
• [x] diff codeclimate #2687
• [ ] diff junit
• [ ] results codeclimate
• [ ] results junit

The output type can be -o junit and -o codeclimate