Update README.md

I spent 8 freaking hours figuring this out.  Instructions related to working around this bug:
https://github.com/mitchellh/vagrant/issues/3139
Merge branches 'develop' and 'ft_vagrant_samba' of https://github.com/EliAndrewC/magfest into ft_vagrant_samba
only try mounting as smb if on windows.  should be significantly faster than the default install.

 also confirmed this branch now works when well you bring it up under windows.

 MY BATTLE IS WON, for now.