Bugfix for empty words

Bugfix for empty words

The \b consider only ASCCI as letter. So diacritics are considered as non word.
and a word like leçon is splitted in 2, "le" is empty word, and the search is done
on çon (which is not french [1], so has no result)

[1] con (without the cedilla) is a french word, but I won't tell you what it means...
anyway, there are probably no "con" in most catalogues ;-)

Signed-off-by: Chris Cormack <crc@liblime.com>
Signed-off-by: Joshua Ferraro <jmf@liblime.com>