Add Rsnapshot package

[damascene]

Rsnapshot is a perl software that do snapshot style backup where only differences take extra space. for example you can have Monday and Tuesday backups where each one is an exact image of how file was in that day. so you can easy go back like time machine.

"rsnapshot is a filesystem snapshot utility based on rsync. rsnapshot makes it easy to make periodic snapshots of local machines, and remote machines over ssh. The code makes extensive use of hard links whenever possible, to greatly reduce the disk space required." rsnapshot.org

I'ts an open source software, It's available on major Linux distributions.
http://rsnapshot.org/