Checks if we're under systemd, and if so, ensures that fbcp isn't
mentioned in /etc/rc.local, and installs a new unit file to start
fbcp at boot, after network.target.

If not under systemd, retains the old rc.local behavior.

I note this is the only place that the $SYSTEMD var actually seems to get
checked.  I can't, at this time, vouch for what would happen on a sysvinit
box.

just breaks things. sorry to the 1% who have nonstandard apt repo needs

do we even need to specify the dtb?

added all the transforms!