Ensure that Essentials spawn.yml is present

Even if it is empty. The new backup process will complain otherwise.
Fix #112: Make managed users have sensible shells
Be more explicit on what is restored from backups
Add a local backup creation script
Properly handle save on/off with local backups
Add a cron job for local backups
Create the backups dir explicitly
Stop using the mark2 backup system
Explicitly disable the backups plugin in mark2