Support saml2:AttributeValue

Support saml2:AttributeValue,  thanks to jaxbot
Undo the last change

Our namespace is saml not saml2
Finally fixed the namespace issue: in xml query we register custom namespace so saml and saml2 namespaces could be used on the xmls, the problem comes at the getAttributes method that use a saml:AttributeValue string to compare with the tagName, that means that saml2:AttributeValue are ignored. To fix it we will use the prefix to build the string that must be compared with
Removed line

Sorry, I added this line accidentally
Add documentation related to x509/private key SP support on settings
Added additional URL parameters option to the login and logout method of the OneLogin_Saml2_Auth class
Remove debug line
Fix typo
Fix #25. Add getError method to Response, LogoutRequest and LogoutResponse in order to be able to get the causes of return false after a isValid method. The LogoutRequest method now can have a request as parameter and the isValid is not static any more. Improved the test with the new getError method
Update composer version
Fix bug with Encrypted nameID on LogoutRequest
Usability bug

CheckStatus before the number of Assertion.
If the IdP send a AuthFail Status Response we want that our SP mention this problem instead that the SAML Response has not got 1 Assertion.
Add SessionIndex support on LogoutRequest and improve the support on Auth class
Now LogoutRequest and LogoutResponse parser in more Flexible and accept non deflated xml
#27 replace the use of getSelfRoutedNoQuery instead of getSelfURLQuery. Nginx compatibility
Fix typos. Improve getSelfRoutedURLNoQuery method and use it at Auth
Remove unnecessary spaces on SP metadata
Improve XML metadata/ Decrypted Assertion prettyprint
Fix bug in formatPrivateKey method, the key could be not RSA
Show explicit warning message for signed element problem when validating a SAML Response