Batch file version for Windows.

This Pull Request adds a batch file for use on Windows platforms.

If I were you I'd be skeptical of this: I don't write a ton of batch scripts, so this could have some lurking problems. However, it seems to work fine on my machine.

I also haven't provided any installation solution. We can't rely on makefiles because most WIndows boxes won't ship with make. I could write an installation batch script if you think that's useful, but it might be easier just to ask Windows people to copy the script to the right place.