Base: Add anon user to the phys group

This allows anon to shut down and reboot the system.

Fixes #775.

Base/etc/group

@@ -1,7 +1,7 @@
 root:x:0:
 wheel:x:1:anon
 tty:x:2:
-phys:x:3:window
+phys:x:3:window,anon
 audio:x:4:anon
 lookup:x:10:protocol,anon
 protocol:x:11:anon