use bin-wrapper to download and test atom-shell

[kevva]

This is a little cleaner way to wrap an executable. It will download the file and then run it with --version to confirm that it works and doesn't exit with anything other than 0.

[max-mapper]

@kevva this changes the behavior from our approach, which symlinks the atom-shell executable directly at install time, to having node spawn the atom executable. me and @mafintosh talked about the two approaches and thought it would be better if this module didn't actually need to run node in order to run atom-shell, so that's the direction we went.

I don't think we're gonna merge this as it's not a clear win in terms of what we get, but thanks for taking the time nonetheless, I am learning a lot from looking at how you implemented bin-wrapper

[kevva]

yeah, that's cool. it's probably possible to keep the .bat file and still use bin-wrapper for the download stuff if you'd want that.