Doesn't detect UTF-16 files without BOM.

[art-solopov]

I have this file. I produced it by converting some UTF-8 text to UTF-16LE via iconv, which doesn't produce a BOM. When I try to detect its encoding, I get this:

>>> CharlockHolmes::EncodingDetector.detect File.read('text_without_bom.txt')
=> {:type=>:binary, :confidence=>100}

What I'd like to see is the actual UTF-16LE encoding.