ICEauthority test failure, download sample data, vim/emacs to IDEs

I would have kept something along these lines maybe at the end of the list requirements.

#. `MNE command line utilities`_ and Freesurfer_	are optional but will allow you to make the best out of MNE. Yet they will require a Unix (Linux or Mac OS) system, that you can install with a virtual machine.

we will later add a link here to the MNE/FreeSurfer VM....