[mojosetup] Windows support

[Ryan C. Gordon]

> Reding the documentation I see some Windows references, so I think that 
> MojoSetup should work on a Windows machine.

It's not ready to use on Windows, yet. There is some basic support from 
where I started on this, but I haven't written the GUI code at all, and 
I'm sure there are a lot of issues to track down (some obvious, like 
missing support for installing Start Menu items, and some more subtle, 
like deal with paths with '/' chars).

Eventually, I'd like people to be able to use one MojoSetup installer 
across several platforms, but it's not there yet, and won't be ready for 
some time yet, either.

--ryan.