Compatibility with Microsoft ADFS 2.0

Added a short Read Me text file with steps to follow in order to use
PAC4J against ADFS.
Modified SAML2 response validation. NameID is not needed if at least one
Subject Confirmation is present (even without a NameID). BaseID is also
accepted. If NameID is empty, a dummy NameID is used for SAML2
credentials.
I think this is a contradiction to the comment above (building the fake Name ID in the validator). When no "natural" Name ID is found and we create a fake one in validateSubject(), then there is no reason why to throw out an exception, is there?

Or, maybe the exception would be valid in this exact case: No info in the subject found and no subject confirmation is present at all. At least this is how I understood it when I was reading the specification.

What do you think?