Initial algorithm for "prepare-media"

That script distributes the files into several media
directories, based on their sizes. Then, each dir can
be written onto a DVD (or CD or..).
Split encryption to a separate script.
user-backup.sh: use 'incoming' dir as the target.
Cron script for multistage
Merge branch 'master' into multistage
Put Postgres full backups in incoming.
Better encryption script
Prepare-media: fit into backup.
Detect already prepared media.
SPEC fixes.
In setup-postgres, the .conf must be owned by postgres
Prepare for removable-rsync methods.
Add the hal-daemon scripts
Improve rsync-removable.
Fix error handling, dir creation.

Tar may exit with 1 when some warnings exist. Go through that.
Fix handling of exit code at all-backup.
Do list non-removable devices.

This helps for USB disks.
Fix typo on rsync-callout.
Restore root's home for gpg.
Some draft manpages.