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.
You change the sementics of the code as the exception is thrown if no bearer subject confirmation method is found. Please leave the thrown exception unchanged and you can pull up your warning code just before the return statement.