re #117. 
re #117. 

NOTE : `Sentence`.`lang` IN (NULL, '') only retrieves lang = '' entries.

Need to do custom query because there is no way to say 
`Sentence`.`lang` = '' OR `Sentence`.`lang` IS NULL
with CakePHP, it seems.

git-svn-id: 776ea4b3e47339c5b8782ec5e9346c740e073fb4@597 e0e46c49-be69-4f5a-ad62-21024a331aea

hans/tatoeba2,hans/tatoeba2,hans/tatoeba2