SFTP large files with resume until successful

http://blogs.msdn.com/b/granth/archive/2010/05/10/how-to-copy-very-large-files-across-a-slow-or-unreliable-network.aspx

http://winscp.net/eng/docs/resume#automatic

http://www.coreftp.com/docs/web1/Command_Line_FTP.htm

http://www.coreftp.com/forums/viewtopic.php?t=1330&highlight=retry

http://www.thecriticalanalysis.com/2012/03/secret-core-ftp-command-line-switches.html