Tests for NS Article

We need to write tests for NS Article. The tests should at least do the following:

* Install the NS article module.
* Verify that the References dialog search view is present.
* Verify that it is possible to programmaticly save, delete and edit a node of the type ns_article with content in all provided fields.
* Test the NS Article add- edit- and delete form.
* Test that the references dialog links show up in the node form and that they have the appropriate settings.
* Test that the contributor extension is working.