Log Message:
Changes 1.12.0:
	* The test system can now run the tests without requiring dnspython
	  to be installed.
	* The 64-bit version of Python on Windows has sys.maxint set to
	  2^31-1, yet passes 2^63-1 as the "unspecified bound" value in
	  slices.  This is a bug in Python as the documentation says the
	  unspecified bound value should be sys.maxint.  We now cope with
	  this.
	* When reading from a masterfile, if the first content line
	  started with leading whitespace, we raised an ugly exception
	  instead of doing the right thing, namely using the zone origin as
	  the name.
	* Added dns.zone.to_text() convenience method.
	* The /etc/resolv.conf setting "options rotate" is now understood
	  by the resolver.  If present, the resolver will shuffle the
	  nameserver list each time dns.resolver.query() is called.  Thanks
	  to underrun for the patch.  Note that you don't want to add
	  "options rotate" to your /etc/resolv.conf if your system's
	  resolver library does not understand it.  In this case, just set
	  resolver.rotate = True by hand.
	* Escaping of Unicode has been corrected.  Previously we escaped
	  and then converted to Unicode, but the right thing to do is
	  convert to Unicode, then escape.  Also, characters > 0x7f should
	  NOT be escaped in Unicode mode.
	* dns.rdtypes.ANY.DNSKEY now has helpers functions to convert
	  between the numeric form of the flags and a set of human-friendly
	  strings.
	* RRSIGs did not respect relativization settings in to_text().
	* dns/rdtypes/IN/APL.py: The APL from_wire() method did not accept an
	  rdata length of 0 as valid.
	* dns/ipv6.py: Add is_mapped()
	* dns/reversename.py: Lookup IPv6 mapped IPv4 addresses in the v4
	  reverse namespace.
	* dns/zone.py: Do not put back an unescaped token.  This was
	  causing escape processing for domain names to break.
	* dns/message.py: Making a response didn't work correctly if the
	  query was signed with TSIG and we knew the key.
	* dns/query.py: Fix problems with the IXFR state machine which caused
	  long diffs to fail.