snapr is yet another rsync-based python backup script

The main features are:
1) a series of daily.1, daily.3, etc. are auto-renumbered,
   so it is safe deleting a repository in the middle
2) permissions and owners can change without causing a
   new backup
3) rsync's hardlink feature is used
4) continuation of aborted backups

Missing features are:
1) snapr log-file rotation
2) non-verbosity
3) restoration of permissions and owners

Command examples:

  cd /destination/dir || exit $?
  snapr -s -i daily /media

or synonymously

  snapr -s -i daily -d /destination/dir /media

rsync pull (no ssh allowed yet, only pure rsync):

  snapr -s -i daily -d /destination/dir rsync://server/media