Update iconv-lite

0.2.7 doesn't support cp932. 0.4.2 does. A problem: iconv-lite doesn't have a default encoding anymore (I asked for the previous behavior to be restored in this PR, but the author decided against it: https://github.com/ashtuchkin/iconv-lite/pull/67) so I wrote a possible solution for dealing with this change (at the very least, it gets tests passing and works in my application).