* Allow the URL a user is sent to after logging out to be customised
This is required for any authentication system that has a magic URL for logging out (e.g. /Shibboleth.sso/Logout).
* Allow auth plugins to return a username
This is a bit cleaner than the current auth flow, which special cases e.g. http authentication
* Add some tests, defaults and documentation
* Add single sign-on authentication mechanism
* Make HTTPAuth use the authExternal/getExternalUsername methods
* Add to acknowledgements
* Add reset method to Auth
* Refactored authorizers to classes
* Merge changes for #7335
* ! fix php 5.3 incompatibility
* Update ADAuthorizationAuthorizer.php
* Fix get_user -> getUser
* Rename AuthorizerFactory to Auth, fix interface missing functions
* Add phpdocs to all interface methods and normalize the names a bit.
* Re-work auth_test.php AD bind tests to work properly with the new class.
Reflection is not the nicest tool, but I think it is appropriate here.
Handle exceptions more nicely in auth_test.php
* Restore AD getUseList fix
Not sure how it got removed
* fix auth_test.php style
