Add UPN support to sqlite HDB backend
fix for texinfo 5.1

Signed-off-by: Ken Dreyer <ktdreyer@ktdreyer.com>
more texinfo 5.1 hacks

For hx509.texi, we need the copyright macros for both html and info.
Just remove the "ifhtml" conditionals.

For whatis.texi, texinfo 5.1 inserts the sub{} macro inline with no
newlines, so there are errors about @html not being at the end of a
line, etc.
Backwards interop for older iprop peers

Don't abort() when seeing as-yet-unimplemented things we know about.

Patch from Harald Barth <haba@kth.se>.
Merge pull request #35 from ktdreyer/texinfo51

texinfo 5.1 fixes