setup_sdcard.sh: rename systemd to initopts as we use it for more now

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>
setup_sdcard.sh: mkfs.fat 3.0.26 now prints out a warning, just comply to ignore it

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>
setup_sdcard.sh: we need to nuke the partition labels, otherwise mke2fs 1.42.10 will ask for permission

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>
port: machinekit to -c machinekit-debian-stable

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>
chroot: add default group systemd-journal, this will be used by journalctl with jessie systemd backport

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>