Explorer: Browse server side directories and files

This class can be used to browse the structure of server side directories and files.

It can open a given server side directory and retrieve the list of files and the of directories and store them separate class variables.

For each file or directory, it retrieves the name, last modification date, permissions and owner. For files it also retrieves the file size.

The list of directories is always sorted by name. The lists of files can be sorted by name, file size, permissions, last modification date or owner.