Switch from latex builds in Sphinx maths to mathjax

In our new build system workflow detailed in #35 (closed), we do not have Latex installed.

I plan to change our docs to mathjax which uses java-script to render the math commands in all packages. See: https://gitlab.idiap.ch/bob/bob.core/compare/master...condapackage#df0576cbb783bc50b36e1efa3cbe0564a26c8295

If there is no objection, I will just go ahead with this as part of #35 (closed).