DNS Packet manipulation class
This class includes sub-classses that provide methods for creating,
parsing, sending, and receving DNS nameserver packets.
This class is only a container class and generally should never be
constructed. It contains constants defined in RFC 1035 with methods for
converting between the integer and the name values of such constants.
For information on sending a basic query to a nameserver for a specific
record, see Net_DNS_Resolver::query().
