Login page: Return HTTP 401; support JSON requests

			if ( $self->is_user_authenticated ) {

				return 1;

			}

			$self->render(

				'login',

			$self->respond_to(

				json => {

					json   => { error => 'authentication required' },

					status => 401

				},

				any => {

					template    => 'login',

					status      => 401,

					redirect_to => $self->req->url,

					from        => 'auth_required'

				}

			);

			return undef;

		}