[XeTeX] Unicode space characters

[Arthur Reutenauer]

> I remember some people talking about this before but as far as I know 
> nothing came of it; to my knowledge this is the first time a 
> comprehensive set of definitions has been created.

  We had a discussion in August 2007 but it didn't lead anywhere,
indeed.

  And now I think about it, it was on the ConTeXt list :-)

>                                                    If this doesn't 
> belong in the base format itself (which I suspect is probably the case) 
> then I highly encourage you to turn this into a LaTeX package and 
> submit it to CTAN.

  I'm not convinced it should go in the format, but it definitely should
be made into a package for CTAN!

	Arthur