Windows fixes & new features

The win32-specific code looked very suspect to me so I actually tried it on Windows. I can't tell what it was actually supposed to do but it's totally broken; I've added a more useful win32-specific piece that runs `.js` files with `node` so Windows will know what to do with them.

I also added a way for a user to specify a way for helmsman to get metadata for this commands; I use this to specify a function that reads the text of specified commands and gets metadata from comments rather than using `require`.

There's also a lot of cleanup and some linting (sorry, I tend to get a little compulsive about it!)