* Use systemd socket activation
* Pass a new command line argument --systemd-socket-activation to the daemons if running on Linux
* Install .socket files
* Systemd services depend on their sockets
* Implement sd_listen_fds in OCaml
* Set FD_CLOEXEC in sd_listen_fds
* README: add comment about socket paths
* Linux systemd scripts: Rename albatross_stat -> albatross_stats
* Make albatrossd wait for other sockets to appear if --retry-connections is specified
* Connect to log/console before creating main socket
* Disable stats by default unless --enable stats is specified
the socket lock was removed in 58c34907 in favour of a global lock -- but the
bootup used an iter_p for create (which is usually called with the lock being
held by the caller)
checks (platform-dependent) all required executables
Vmm_unix.prepare/exec execute solo5-{spt/hvt} depending on the image type
(solo5-elftool figures that out), use jsonm to parse output
Vmm_unix: use ip on linux, no longer ifconfig