List a directory in a standardized format by using MLSD
command (RFC-3659). If path is omitted the current directory
is assumed. "facts" is a list of strings representing the type
of information desired (e.g. ["type", "size", "perm"]).
Return a generator object yielding a tuple of two elements
for every file found in path.
First element is the file name, the second one is a dictionary
including a variable number of "facts" depending on the server
and whether "facts" argument has been provided.