get-ppa.sh:  create config directory if missing
config:  Convert to web URLs

Moving to remote host
Add archive signing and rsyncing

Package archive can be signed with a key in scripts/gnupg.

- Add -k option to dump package signing key
- Add reprepro command-line signing option
- Manage GNUPGHOME variable from config
- Add 'SignWith' directive to conf/distributions

Package archive can be rsynched to another host

- Add RSYNC_TARGET configs
- Add cronjob.sh script to update archive & run rsync
Add sample crontab
Only sync machinekit repo without command-line switch
Add -q option for quiet cron runs
Make runs quiet

At every five minutes, this is a lot of email.

- Add '-q' option to get-ppa.sh

- If no repo updates are configured for a codename, don't run, since
  this creates warnings

- Add '-q' option to rsync