It actually breaks "zh:big5" so I'm going to hold-off a bit. Adding more
language and charset support is slowly starting to show the limitations
of our legacy multi-byte charset supports, since I haven't really
touched these since the original implementation of Mozilla.
It might be time to start reviewing these parts of the code.
The test file contents comes from 'Μαρμότα' page on Wikipedia in Greek
(though since 2 letters are missing in this encoding, despite its
popularity for Greek, I had to be careful in choosing pieces of text
without such letters).
I did this to improve the model after a user reported a Greek sutitle
badly detected (see commit e0eec3b).
It didn't help, but well... since I updated it with much more data from
Wikipedia. Let's just commit it!