Add root drive mapping to default config file

[mike at theoretic.com]

> - its insecure, since you can write everywhere you want
> and some filesystem corruption still exist today.

Only if you run Wine as root. What makes us think we trust Linux software
more than Win32 software?

> - it will cause recursion/drive change problems =>
> example : what will be the current drive/directory
> if you access the fake C:\windows
>  via Z:\home\user\fake_c\windows ?

Good question. I guess the algorithm must be able to deal with that
though, as I've been running with / mapped for months and it hasn't caused
any problems that I can see. Simply chopping out subtrees if they are
mapped elsewhere would work.

> On my RH box I have a drive called W: that contains wine sources and P:
> contains programs/.
> If I am in W: (wcmd) and I do 'cd programs', wcmd now says P:\.

Yes, that might be a bit confusing (if you use wcmd), but for newbies
having the "Wine cannot find executable" error is even more confusing.

Well, I'm not really bothered either way, but something would need to be
done to address those problems I think.