[XeTeX] Roman Numerals as stylistic alternatives

[Arthur Reutenauer]

> Then why is Unicode proposing / imposing it that way?

  Unicode has nothing with it; OpenType is the font standard.  And as to
why it proposes / imposes / disposes it that way, it's hard to say,
because it's simply ill-advised to use font substitutions for what
you're looking for.  You want the solution Ross suggested; although the
font hacks sketched by Enrico, Matthew, and Peter surely would be great
fun.

	Arthur