texinfo pretest 4.9.91

I put another texinfo pretest up at
ftp://alpha.gnu.org/gnu/texinfo/texinfo-4.9.91.tar.gz.  I'm hoping we're
getting close; there's no new features in particular I want to add at
this point, but presumably plenty of bugs remain.  Please give it a try
if you can and report any problems.

Thanks,
Karl