Repairing tests and regressions
Consistently use `Security::getCurrentUser()` and `Security::setCurrentUser()`
Fix for the logout handler to properly logout, some minor wording updates
Remove the login hashes for the member when logging out.
BasicAuth to use `HTTPRequest`
API Add HasRequestHandler interface
API Refactor Link() and url handling behaviour from Controller into RequestHandler
API RequestHandler classes now must define url_segment to have a default Link()
API Clean up redirectBack()
