New Directory class for use in file systems; file systems need to publish their root directory as a subclass of this class. git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4587 a95241bf-73f2-0310-859d-f6bbb57e9c96
git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4563 a95241bf-73f2-0310-859d-f6bbb57e9c96
git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4462 a95241bf-73f2-0310-859d-f6bbb57e9c96