API: test "correct" capitalization of key header

Test what we document, not what the code checks for.
ship notify tool
read ALLOW-AXFR-FROM from the backend with the metadata
Add pdns-auth security polling status for Fedora
Merge pull request #1865 from mortenstevens/master

Add pdns-auth security polling status for Fedora
Add pdns-auth security polling status for Debian
Merge pull request #1866 from zeha/secpoll-debian

Add pdns-auth security polling status for Debian
Throw is serial won't fit into uint32_t, fixes #1009
Renamed strtoui to pdns_strtoui, requested by @ahu
Merge pull request #1864 from cmouse/check-serial-overflow

Check serial overflow
prevent warnings on 32 bit
Allow changing the Sockaddr in ComboAddress
Reuse existing connection when possible
Merge pull request #1868 from cmouse/remotebackend-keepalive

Remotebackend keepalive support
Remove leftover function prototype

No function body is to be seen anywhere.
Remove unused define
Fail if we can't find libopendbx
Rename variable to be consistent with the rest
Check for libopendbx with pkg-config
Merge pull request #1869 from zeha/cleanup

Misc. cleanup