[3109] Initial text import for Contributor's Guide
[3035] Moved the Dhcpv4Srv test classes to the common header.
[3035] Added stub implementation for the function processing client FQDN.
[3035] Implemented DHCPv4 Client FQDN option processing.
[2300] define new statistics counters in Xfrin spec

  open
  openfail
  close
  connfail
  conn
  senderr
  recverr
[2300] use _master_addrinfo[0] for address family in _get_ipver_str()

Because _get_ipver_str() is referring to an attribute of NoneType when it is
invoked earlier than init_socket() and when the socket object is None.
[2300] override some methods of asyncore.dispatcher in XfrinConnection

This is for implementation of statistics socket counters for Xfrin
[2300] add unit tests for statistics socket counters introduced in Xfrin
[2300] set self.tsig_key_name in XfrinConnection.__init__()

Because this is used for outputting an error message when failing to connect to
master. (This is not a related change.)
[2300] check statistics socket counters for Xfrin in lettuce test
[2300] document in the man page about statistics socket counters introduced in Xfrin

  open
  openfail
  close
  connfail
  conn
  senderr
  recverr
[3035] Implemented DHCPv4 srv function to process an FQDN option.
[3035] Added functions to construct DHCID object from raw buffer.
[3035] Basic implementation of the function which computes DHCID.
[3035] Implemented functions to compute DHCID from Client Id and HW address
[3035] Renamed DhcidComputeError to DhcidRdataComputeError.
[3035] Include HW type in the digest when generating DHCID from HW addr.
[3109] Extra details added to Contributor's Guidelines
[3035] Generate NameChangeRequest when new lease is acquired.
[3035] Added functions to check that two leases belong to the same client.