PROPOSAL: standard run levels (draft 1)

[Daniel Quinlan <quinlan@transmeta.com>]

Proposal for standard run levels, going after requirement #6 ("define
standard run level mappings") in draft 2 of the init file requirements.

This is based on my best estimation of Linux common practice.

------- start of cut text --------------
0       halt
1       single user mode
2       multiuser with no remote networking
3       normal/full multiuser
4       reserved for local use, default is normal/full multiuser
5       xdm or equivalent
6       reboot
------- end ----------------------------

tytso also mentioned that he uses runlevel 7 as a power-conserving
runlevel for long airplane rides using his laptop.

- Dan