initial stab at 'ALIAS' or 'ANAME' records for PowerDNS. To use, set an ALIAS record on your apex. Secondly, configure PowerDNS with 'recursor=a.recursor.ip'. Sample zone:

@	IN	SOA	ns1 ahu 2014091619 7200 3600 1209600 3600
@	IN	NS	ns1
@	IN	NS	ns2
www	IN	CNAME	xs.powerdns.com.
ns1	IN	A	1.2.3.4
ns2	IN	A	4.3.2.1
@	IN	ALIAS	www.powerdns.com.
@	IN	MX	25 outpost.ds9a.nl.
elsewhere	IN	CNAME	@

Semantics are that real records override the ALIAS. We only reach out to the alias record if nothing else matched.
this currently breaks ANY queries for the apex btw.
some documentation
remove spurious 'any' (thanks seth) plus clarify CNAME walking
typos
EDNS0, AXFR details, rationale, some wording improvements
Merge branch 'master' into alias

Conflicts:
	pdns/dnsproxy.cc
Set BOOST_CPPFLAGS and THREADFLAGS globally

Should fix #1523
Link binaries explicitly with libpthread if needed
Darwin has pthread in libc

Fixes the following warning:
clang: warning: argument unused during compilation: '-pthread'
Don't look in system include paths for pdns headers
Merge pull request #1791 from rubenk/reduce-nr-of-boost-cppflags

Set BOOST_CPPFLAGS and THREADFLAGS globally
Merge pull request #1792 from rubenk/fix-unused-argument-warning-on-osx

Fix unused argument warning on osx
Replace autoconf variable with automake variable
Add libraries with _LDADD
Add libdl to _LDADD instead of _LDFLAGS
Break up long lines
Don't add generated sources to _SOURCES
Conditionalize sqlite libs
Move some stuff up

No functional changes
Remove unneeded flags from tools