remove login_referer field
fix form placement
add Security component
prefix login referer with slash
remove Security component as it is only need for user login
add SecurityComponent, refactor, fix redirects for testing, handle login_referer only via session
add a check that at least one active user remains before deletion
add a general CoreControllerTest as a base for all Core plugin controller tests
completely refactored, add missing tests, 100% code coverage
remove return statements after redirects at the end of actions
add _makeAjax method for easy ajax testing
add POST request requirement and narrow saveMany to the 'position' field
refactor/rewrite tests, add missing assertions