Add support for deploying to more than one host for rsync, sftp and ftp

[siebertm]

I recently needed to deploy to a load-balanced multi-node setup and had to adapt the code to make this work. Since we don't have any access to FTP or SFTP, I adapted these methods to, but could not test it, though the changes are pretty straight-forward. Maybe someone should do a quick test for that, too.

RSync works, I already deployed something.

[gilgen]

I've got a similar setup I'd like to deploy to, this or something like it would be great.

[runlevel5]

@siebertm Would you be able to get the branch up-to-date?