Attempt basic test coverage

Hot on the heels of #926354: Site verification deletion uses D6 API, it looked logical to add some basic test coverage to ensure the module works consistently. I've attempted to write a basic test to add a site verification entry, look whether it shows up on the front page (this just covers the META tag), then remove it. So such a test would catch #926354: Site verification deletion uses D6 API not working.

Unfortunately I do not have much experience in testing multistep forms in the way you have them set up and I could not find good answers, so instead of dumping what I had, I decided to post as a patch and see if we can fix it up and make it work.