Uploaded doxygen documentation does not build LaTeX formulae

See e.g., http://eigen.tuxfamily.org/dox-devel/classEigen_1_1FullPivHouseholderQR.html

It seems this has only been reported via other channels, so I'm opening an issue here.

@ggael Can you check this? Probably this is just due to a missing TeX installation on the machine that builds/uploads the docu.