public static function listAll() {
		$r = array();
		foreach( static::$fixtures as $class => &$state ) {
			if( $state == null ) {
				$state	= class_exists($class, true) && is_subclass_of($class, 'Orpheus\Publisher\Fixture\FixtureInterface');
			}
			if( $state == true ) {
				$r[] = $class;
			}
		}
		return $r;
	}