[bug-libunistring] backward iteration

[Ben Pfaff]

I submitted a module to support backward iteration in Unicode strings in
November 2010, and then a revised version based on Bruno's feedback in
January 2011.  After I received no feedback at all on that version, I
submitted the same thing again in February 2011, which also gathered no
feedback at all.

Here is the repost from Feb. 2011:
http://comments.gmane.org/gmane.comp.gnu.libunistring.bugs/69

I'd still like to get this into libunistring.  Please, if the current
maintainer is interested, let me know and I will rebase and repost
again.

Thanks,

Ben.