SFTP: nlist() didn't return empty directories - now it does
SFTP: nlist() didn't return empty directories - now it does

I view this as a BC breaking change so atm do not plan on
backporting it to 1.0/2.0. eg. now, all subdirectories have . and
.. as "files" whereas before they didn't

danog/phpseclib,terrafrost/phpseclib,danog/phpseclib,phpseclib/phpseclib