piuparts-slave.deb: Depends: sudo

Signed-off-by: Andreas Beckmann <anbe@debian.org>
New master cronjob gather_bts_stats to write bts_stats.txt to master-directory

* master-bin/gather_bts_stats: write bts_stats.txt to master-directory.
* conf/crontab-master: run gather_bts_stats daily.
* master-bin/prepare_backup: backup bts_stats.txt and do not backup
  sources.txt.

Signed-off-by: Holger Levsen <holger@layer-acht.org>