Item: show a folder icon for each item
Thumbnails for files (use current presenter)
Image Presenter: Create (and cache) thumbnail image
Styling for thumbnails
Item: whole entry as link
Archive: return visible content of a directory, stat all files
Directory: Remove deleted/Add new files (no directories yet!)
Archive: file_stat() removes null for missing files
Directory: remove deleted directories recursively from database
Item: item_path() returns path, which can be resolved by get_item()
Archive: get_directory_content() returns only list of file names
Archive: rename data key 'path' to 'archive_path'
Directory/File: Create db entry for new files