gemTextParser
* Removes the last empty lines of text files.
* Removes the last spaces (rtrim) even on preformated texts.
* Lines like "# " are possible, meaning an empty title.
* The line "=>" means an empty link.
GemtextTranslate_gemtext
* FIX: writes the alt text of preformated blocks
* Adds a space when quotation lines have value, otherwise lets ">".
* Adds a space when the link has values, otherwise not.
* A bit of reformating
Christophe HENRY