do NOT install vb on win10TP

[cvieira]

as a kind notice to anyone who ventures to try this;

Do not try to install vb on win10. Upon install, it completely broke my windows installation (got stuck with a black screen after boot).

I made every possible effort to fix it, but finally gave up and had to revert to an old win8.1 installation and restart everything with the tech preview.

hope this serves as a warning/reminder to not try to use the virtualbox right now, at least until there is better support on windows side.