commit: Correct case-insensitive search for non-case, non-ASCII chars. Add tests.

[Aidan Kehoe]

 Ar an triú lá de mí Feabhra, scríobh Michael Sperber: 

 > Aidan Kehoe <kehoea at parhasard.net> writes:
 > 
 > >  Ar an t-aonú lá is triochad de mí Eanair, scríobh Michael Sperber: 
 > >
 > >  > Let me know if you need more info---I couldn't convince gdb on my
 > >  > Mac OS X box to produce a backtrace right away, but I'll have more
 > >  > time tomorrow.
 > >
 > > Ideally, I’d like the entire buffer being searched, together with the output
 > > of M-: (current-case-table) RET, both saved using escape-quoted. I can’t
 > > provoke an assertion failure with 
 > >
 > > (search-forward "Patrick Mézard <pmezard at gmail.com>" nil t)
 > >
 > > on its own, so I need more context.
 > 
 > The buffer is empty.  I can reproduce the problem by creating a vanilla
 > empty buffer, and then doing M-: (search-forward ...).

Probably because GNUS’ modifications have affected the global case table. 
What does M-: (current-case-table) RET give?

-- 
¿Dónde estará ahora mi sobrino Yoghurtu Nghé, que tuvo que huir
precipitadamente de la aldea por culpa de la escasez de rinocerontes?