[Patch] More facets rearrangements

[Benjamin Kosnik]

> Basically, I'm going nowhere ;) I mean, with this patch, the idea posted 
> before the Meeting is implemented, now <iostream> is about 80 KB 
> smaller. And generally I'm rather happy with the rest, seems consistent: 
> a minimal set of locale "stuff" in the locale_classes headers, then the 
> additional features used in the iostreams and finally the rest. Some 
> additional clean ups are maybe possible, but really, as far as I'm 
> concerned, I'm going to work on something else, for now.

OK. I see the collate tie now. Ugh.

Thanks for this! It does make the dependencies much clearer.

-benjamin