Merge pull request #24 from lorenzogil/master

Don't always sign the logout requests, use what the config says
Removed out commented code
Editorial
Added method - handle_logout_request
Added missing attribute
Editorial
Method response_args should return destination and binding.
Has to remove those when constructing status_responses.
Changed the API, added one method (find_nameid) and removed two (publish, published).
Mongo DB has special demands on keys in dictionaries, has to take care if that.
File med different storage modules all using Mongo DB as backend.
Editorial
Moved Mongo DB based class to another module.
Dealing with different storage modules
Editorial
Editorial
Fixed tests
Some more descriptive text.