• Improved interface to mod_ssl for fallback handling. Backward compatible to previous mod_ssl
  patch, but fallbacks will not work.
• Provide a temporary, self-signed certificate with a speaking command and domain name if we
  have no other cert for a Managed Domain, yet. Refs github issue #32
• Continue to provide expired or not-completely matching, existing certificate for a Managed
  Domain until the renewal was successful. This is helpful when one adds a DNS name to
  a MD, so the previous domains can be served while a new cert is requested.