Fixed https://github.com/jhy/jsoup/issues/288

Let me know if you want me to patch it in another way. 

Jsoup as a HTML parser may encounter content in different charset including supplementary characters (that happens regularly in any non-English regional content), and it would be great if it can handle those characters properly.

p.s. Just in case if the patch is not accepted, would let me know if there are any workaround. thx