Documenting xft options

[Chrysostomus]

I think it would be good to document xft related options, like how to pass fonts in xft form or how to turn on antialiasing. I had to google the former from other places, and still have no idea how to do latter.

[krypt-n]

See this list of fontconfig options for selecting a font. I don't think we need to document anything there, if we mention that this fork accepts fontconfig specifiers.

[Chrysostomus]

Thanks for the info =)