NAR - currently works weel enough to manage hosts and services for
straightforward cases.  The server needs some config options and I need
to decide whether to use cmdline options or a config file.  In the
interim I'm using hardcoded Icinga directory locations.
Initial checkin of the libs and (sparse) tests
the prereqs were missing from Makefile.PL
tidy up repo, these meta files don't need to be checked in