Import 20h's svc.

This was taken from: http://git.r-36.net/svc/

Thanks!
Remove rc.d
sbin/ is a symlink to bin/ so no need to add it to the PATH
Add /etc/fstab
Mount root as rw at boot time
Use OpenDNS by default
Embed LICENCE in svc
Add poweroff/reboot scripts
Save the system clock properly in rc.shutdown
Minimize the sleep time to 3 seconds instead of 5
Check if rc.svc and rc.local are executable and only then run them
Make rc.local non-executable by default
Fork getty from rc.init so we can bypass rc.svc if needed
Export PATH in init scripts for anyone needing them
Sanitize umask
Add usage examples for svc
Add video group
Add audio group
Signal init for reboot/poweroff
Add .xinitrc