WWW::MeGa::Item::Folder - Representing a folder / album in WWW::MeGa
looks for a file named by the
album_thumb config parameter,
THUMBNAIL in this folder and return it if found.
If not, select the first item of the directory as thumbnail.
returns a list of all files in the directory.
returns the first file of the directory.
return the item before and after the item specified by $path in the represented directory.