New option 'session_timeout'

This option can help keep system resources when ftp handles a lot of connections. Default value for FTPFactory.timeOut is 600 seconds and it is very much, I suggest default value set to 60 sec.

Also, I think, need to add same option for sftp and update man and tests :-)

PS: option 'connection_timeout' hard to understand, there is set connection timeout for swift, but not for ftp session. I was able to figured it only from source.