Fix remove notebook issue reported by @atorok.
 Add support for autoSaveHtml

 Possibility to auto save html each time the md is saved.
 Usefull if one wants to sync and expose in a browser
If autoSaveHtml==True, edited notes will be autosaved to html/notes/
folder.
Export to html can be complete html (with css) or only html.
Autosaved html is html only, they share a css file.