parse non-ascci filenames

failing spec, not sure how to fix :/

when I remove the rescue in `def element` I get:
```
Mail::ContentTypeElement can not parse |application/msword; name="Êëèêîâàÿ_ðåêëàìà.doc"|
       Reason was: Only able to parse up to application/msword; name="Ê
```

@jeremy @bf4