itextsharp.xmlworker.dll 用于html 转PDF和图片
* HTML to PDF (PDF/UA) conversion
* PDF Redaction
* SVG support
* Better language support (Indic, Thai, Khmer, Arabic, Hebrew)
* PDF Debugging for your IDE
* Data Extraction
* Better continued support and bugfixes
* More modular, extensible handling of your document workflow
* Extra practical add-ons
* Encryption, hashing and digital signatures
