Please detail each test in documentation

Hi,

I think it would be great and useful to improve the documentation so that it states what each specific test does, what it looks for, and what its aims are.

This can most of the time be taken from the rkhunter script comments in the code, which is currently the only way to have more precise information on what a test is about.

This way is definitively not user-friendly, and things could be quite easily improved.

Thanks again for your work.

Cheers,
Julien