* Added underlineSpan builder function. This can be easily updated if needed. The purpose is for Readers to transform underlines consistently.
* Docx Reader: Use underlineSpan and update test
* Org Reader: Use underlineSpan and add test
* Textile Reader: Use underlineSpan and add test case
* Txt2Tags Reader: Use underlineSpan and update test
* HTML Reader: Use underlineSpan and add test case
hftf