It looks like [it is recommended that you use `getAppUserDataDirectory` instead of `getHomeDirectory`](http://hackage.haskell.org/package/directory-1.0.0.0/docs/System-Directory.html#v%3AgetHomeDirectory). Does that make sense in this case?

Also, I'd like to use the same directory for some `elm-get` information. How about having the root directory be elm/ and the sub directories be named for the specific sub-project. So there'd be `elm/repl/`, `elm/get/`, etc. Reasonable?