* Removes "^" to disable text decoration line-wise.
* Split HTML generation in two: parsing and translating.
* Create class to handle gemtext parsing.
* Create class to translate to HTML.
* Create class to generate back gemtext (for future test cases).
* Uses generators to parse then translate.
* Fix: 404 doesn't occur for an empty file.
* Page 404 fully generated by HtmGem itself.
* CSS is no longer incorporated in the HTML page.
* Handle CSS inclusion by addCss() calls.
Christophe HENRY