Add IAuthenticator
Improve logic/auth/__init__.py bad logic (data_dict={})
Slight refactor of logic/auth/__init__.py for more pythonic plus store found object
Saml2 - add check_access calls to some user actions
Merge branch 'release-datagov' into release-datagov-saml2
[saml2: Use own cache as a test was triggered and this is safer
@auth_sysadmins_check auth function decorator
Merge branch 'release-datagov' into release-datagov-saml2

Conflicts:
	ckan/logic/auth/__init__.py
    IAuthenticator fixes