Merge branch 'patches/bug4594' into devel * patches/bug4594: FTP: Extended AUTH TLS config option. FTP: Fixed SSL data connection. FTP: Fixed typo in PBSZ error message. FTP: Support ending the TLS control connection with REIN. FTP: Added configuration flag to require AUTH TLS. FTP: Support AUTH TLS (RFC 4217). FTP: The ftp server is always the server side of TLS. FTP: Splitted send() into low_send() and send(). FTP: Prepare for supporting AUTH TLS (RFC 4217). Protocols: Added StartTLSProtocol.