Support Windows through powershell

[mniak]

I created a powershell version of the script that works reasonably well.
I think this could be released as some kind of alpha.

Basically two changes:

1. Add an install.ps1 template file
2. Create a conditional at the endpoint that generates the script that detects if the user agent is a powershell and if so, renders the renderization of the install.ps1 template.

Closes #2

[mniak]

Someone?

[mniak]

@tj and @wallyqs, could you look into this?