bug in fontinst 1.801: rounding problems (was: duplicated ker nings)

[Alan Jeffrey]

Gosh, what a remarkable bit of detective work, well done!

I guess the question is now what the fix is: peraps all generations of
MAPFONT should go through the `divide by 8 multiply by 8 again' routine to
make sure they're all rounded.  This won't make any difference to dimens
that have gone through the process, and will round others appropriately.

For anyone who's wondering why the code does this in the first place, it's
because otherwise you get overflow errors by multiplying a dimen by a
scalefactor > 1000 (TeX doesn't support fp multiplication, you have to
multiply by an int then divide by another int).

Alan.