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.
Merge branch 'master' of https://github.com/leleuj/pac4j
Merge branch 'master' of https://github.com/leleuj/pac4j
Modifications recomended by reviewers of pull request 93 at leleuj/pac4j.
Merge pull request #93 from jkacer/master

Compatibility with Microsoft ADFS 2.0