dnsproxy uses sendmsg instead of sendto
dnsproxy.cc and nameserver.cc use addCMsgSrcAddr() to add a source address control message before sendmsg
fixes PowerDNS/pdns/657

I noticed this as a result of the changes in 3.2 whereby each receiver gets its own distributor - whenever the dynhandler calls ->getBackend() it will only find the one in its' current thread, so reload won't propergate to backends within other threads.

However, I suspect this condition has always been around as a race - if I have multiple distributors and I call reload; one thread is issuing reloads while all the other backend threads are currently executing (potentially). I guess if you call reload in previous versions on a highly loaded server with multiple backends you could probably get it to crash.

The attached patch changes it so that each backend has a variable which is changed to signal that a reload or rediscover has been requested. When processing gets to an appropriate point ie before it next queries the backend database, such an operation will be run. Note that it is not run in ::get as we don't want a backend to be reloaded between performing a lookup and getting the records.

This patch means that reload/reinitialize are not done straight away as in previous versions, but on a moderately loaded server this should not be a problem as they will be performed the next time a backend is called.
Terminate pdns process after SIGINT
Sets d_server to NULL on failed initialization
Enable zeromq for remotebackend
Fix typo in TEST_ENVIRONMENT to allow zeromq test suite to run
Merge pull request #1162 from cmouse/nullify-webserver-d_server

Sets d_server to NULL on failed initialization
Add primary key to schemas
Fixed goracle schema white space
Wait until processes die before exiting
libzmq3 compability fixes
Update documention
Merge pull request #1163 from cmouse/gsql-add-primary-key

Add primary key to schemas
Merge pull request #1124 from cmouse/remotebackend-0mq-connector

Remotebackend 0mq connector
nit
Use sql file instead for goracle schema
Merge pull request #1164 from cmouse/goracle-docs-update

Use sql file instead for goracle schema
from orbit. just to be sure.
don't bomb out for unused modules during remotebackend make check, thanks @cmouse