braindump for windows

this isn't meant as a solution, but as a place to experiment with window support (as time permits)

symlinks apparently work if:

- [x] the user is an admin (confirm)
- [x] the users policy allows them (couldn't get this to work)
- [ ] get feedback from @joliss 

with more hacks i was able to get ^^ sorta booting, but I ran into other problems (like missing files) and I failed to have time to investigate further today
This writes `undefined` into the file. Perhaps pass an empty string as second argument to future-proof it?

Other than that it looks good to me.

@raytiley and @stefanpenner, are you going to be around for maintaining the Windows parts on this? I can't maintain it myself because I don't have a Windows machine around (one that's set up for development anyway).