Add support for Document.OutputSettings and baseUri

[pmetras]

Hello,

It would be nice to add support for the Jsoup.clean() extended call http://jsoup.org/apidocs/org/jsoup/Jsoup.html#clean%28java.lang.String,%20java.lang.String,%20org.jsoup.safety.Whitelist,%20org.jsoup.nodes.Document.OutputSettings%29, with Document.OutputSettings and base Uri. This will let the programmer specify if she wants XML or XHTML output, or the encoding of the resulting text.

Thanks