Design ideas about iterators

[Cyrille Berger]

> That said, I haven't got much of a clue about what to do about hiding
> QUANTUM, and even less about iterators, so if you can whip up something
> that works, we can use it, and refine/refactor later.
Maybe we can use template, but as they are often ugly (look at the stl), we 
should be very carefull, and we should add a lot of comment.
-- 
--- Cyrille Berger ---