addrconf: exposed lease to/from xml utilities
addrconf: exposed netbios node mapping helpers

And of course, use mapped variant in lease-xml.
dhcp4: moved tester code into separate file
dhcp4: added request lease dry-run mode
dhcp6: moved tester code into separate file
dhcp6: added request lease dry-run mode
dhcp4: added lease-xml output to tester
dhcp6: added lease-xml output to tester
ibft: re-added ibft parsing utilities in C

Added also root-dir handling to pass tests with our
faked ibft sysfs tree in testing on non ibft system.
dhcp6: write also hostname to xml lease
addrconf: static xml lease writting/parsing utils
addconf: update allow static lease to update resolver

This is required for iBFT leases and solves bnc#864131.
client: workaround to consider wait-for-interfaces

Get the WAIT_FOR_INTERFACES variable from environment, which is
sourced in the service file to not timeout too early and also
allow the users to increase it (see bnc#863371, bnc#862530).
dhcp6: fixed to not remove lease in offer mode
dhcp4: fixed to commit lease release
Merge pull request #171 from mtomaschewski/dhcp-test-lease