+ o Added FORWARDING macro for generating forward-only zones.
+ o Added BLACKHOLE macro for blackhole zones as per RFC 6303.
+ Blackhole zones in example cf/domains updated to use this macro.
+ o Given that BIND does not support combination of options { }
+ sections, we do not generate them any longer -- write the
+ appropriate options to BIND config file and include the part
+ with the list of zones generated by NSC from there. This means
+ that BIND_OPTIONS, FORWARD and SLAVE are gone.
+ o When contents of a zone do not change, the version number is
+ not incremented.