- not used function removed
 - DHCP6_HOOK_PACKET_RCVD_SKIP message typo fixed

- callouts called using HooksManager::callCallouts
- removed Dhcp6Srv::getServerHooks() and getHooksManager() declarations.
- updated sendPacket comment (reception->transmission)
- documented getCalloutHandle()
- indentation fixed for getSubnets6()

in D2 unit test.

Don't warn about static cast of function pointer print.

Synchronize the workthread and main thread in the authoritative server,
by providing callbacks executed in the main thread after a work in the
workthread is completed.

To silence cppcheck.

Conflicts:
	src/bin/d2/Makefile.am
	src/bin/d2/d2_messages.mes
	src/bin/d2/tests/Makefile.am

This change added in response to a "make distcheck" failute on one
of the build systems.

These *.log and *.trs are created in all the tests/ directories when
gtest unittests are run with automake 1.13.4.

See: http://www.gnu.org/software/automake/manual/automake.html#Parallel-Test-Harness

Only OSX uses ".dylib" as a suffix for shared libraries.  Adjust
configure.ac so that the operating system can be better determined,
and ensure the hooks tests use the correct suffic for the test shared
libraries.

The hooks system can only load shared libraries, even if BIND 10 is
linked statically.