Add /etc/X11/xorg.conf-auto-armsystem

Xorg from Raspbian won't start with the default settings from
xorg.conf-auto-pc  Now default settings for armsystem can be
placed in rootfs-skeleton/etc/X11/xorg.conf-auto-armsystem
Merge pull request #469 from woodenshoe-wi/raspbian-changes2

Raspbian changes2