random-seed: add little tool for saving/loading random seed on shutdown/boot, but don't enable it by default

systemctl: skip writing of utmp if we booted using systemd, under the assumption that systemd-update-utmp is used

units: move runlevel[2-5] links to /lib because they are legacy and hence should not be as obviously in sight. The user may still override them by placing links in /etc

service: rename Type=finish to Type=oneshot and allow multiple ExecStart= lines for oneshot services

In contrast to the other service types oneshot services are usually not
long lasting and there's not necessarily a single clean main process for
them. This change allows multiple ExecStart= lines for this type of
services so that the admin/developer doesn't have to arbitrarily pick on
of various sequential commands as the "main one".

systemctl: properly detect whether taling to systemd via D-Bus worked before falling back to upstart/initctl

https://bugzilla.redhat.com/show_bug.cgi?id=623561

https://bugzilla.redhat.com/show_bug.cgi?id=623430

target: don't synthesize a runlevel property for targets anymore since we don't need it anymore and it is crutfy