GitLab

 - Added rationale for ptimeToText, durationToText
 - Added missing headers
 - Removed the default values in addValue()
 - StatsDuration is now passed by reference

 - {ptime,duration}ToText moved to lib/util
 - missing comments added
 - EXPECT_EQ -> ASSERT_EQ
 - several consts added
 - protected methods are now private in Observation
 - tabs converted to spaces

because that directory name doesn't exist with the installed version
of kea.

This is trivial and I commit to master without review.

The erase function was called on the const_iterator which caused build
failures on Linux boxes with gcc. This fix was okayed on jabber.

fqdn_unittest.cc
    TEST_F(NameDhcpv4SrvTest, emptyFqdn) - now also verifies that the
    lease is added to the database following a REQUEST and that when
    it is retrieved from the database its hostname matches the generated FQDN.

src/bin/dhcp4/dhcp4_srv.cc
    Dhcpv4Srv::assignLease() - added logic to update the lease DB with a
    generated FQDN when not doing a fake allocation

src/bin/dhcp4/tests/fqdn_unittest.cc
    added TEST_F(NameDhcpv4SrvTest, hostnameReservation)

Do not remove duplicates if other MessageInitializers held them.
Also, do not remove message from the dictionary if removing the
duplicate.