Doxygen for www site

Hi @evanmiller ..

Been around the houses trying to find how to publish "web pages" and manual,
without the gh-pages
 
eg gitlab has "pages" and can knock out doxygen/sphinx et all

So my plan is to just publish the doxygen docs to mdbtools.github.io..

But this is also handy as will bring the source and documentations together
albeit in a different repos...

