The default is that hiniting is enabled, which causes some text
metrics (notably width) to be rounded to integer values, which makes
spacing more consistent. This default is backward-compatible. The
non-default 'unaligned mode refrains from rounding, which makes metric
information scale correctly and improves output for PS/PDF (such as
Redex output).
The `text' function from `slideshow/pict' defaults to
disabling hinting --- which is consistent with its default to combine
text instead of drawing character-by-character -- so slides and Redex
inherit the improvement.
Treat a "face" as a font description only if it has a comma,
otherwise go back to treating it as a family name.
This change fixes the problem of parsing "Times New Roman"
as "Times New, Roman".
It's not clear that any limit is still needed, and probably
font sizes should be liberalized to reals instead of
integers (but I don't want to spend that kind of time
right now).
