Endless loop on Windows

[MajorBreakfast]

function check() {
  console.log(dir);
  return false;
}

findup(process.cwd(), check, cb);

cb is never called. Instead the output is:

C:\
C:\
C:\
C:\
C:\
C:\
...

This also happens if I define the file via string, e.g. 'config.json'.

I didn't test it on Mac but my guess is that this is a Windows thing.

[MajorBreakfast]

Must be because of https://github.com/Filirom1/findup/blob/master/index.js#L68
This is not a very good end condition then :)

[MajorBreakfast]

Closing this in favor of PR #5