[XeTeX] letter spacing

[Ricard Roca]

I don't mean letterspacing with lower case, to emphasize, etc. In that 
situations it looks awful.

But with uppercase or smallcaps it is often needed for good typography, 
specially with serif fonts and titling.

So the only way I think it could be done is to generate a new font file (e.g. 
with Fontforge) with increased spacing between all glyphs, and use this font 
in that situations, but I don't know if every font license permits that, 
because it's like editing the font.

It's the same with slanted fonts, for the ones that doesn't include that 
shape.

Tnanks,

Ricard