most rootless X work are already done in the kernel, xserver and
graphics driver, this patches add the the remaining userspace setting:
- create /etc/X11/Xusername to set rootless X user
- add rootless X user to group video, tty to access /dev/tty[0-4]
and /dev/dri/card0
- grant rootless X user access right to /dev/input/*, /var/log
Signed-off-by: Yu Ke <ke.yu@intel.com>