Goal: Make formulas look nicer in doxygen. * [x] Add doc/doxygen/Doxylocal `+USE_MATHJAX = YES` * [x] Get rid of `\textup`, `\textbf` and `\bf` as they are not properly parsed by mathjax and should not be used in the formulas anyway * [x] See if further commands are not parsed properly Spin-off of the discussion in !1964