Add 'locales/' folder to package.json

[jamesdorfman]

The npm documentation for this package includes the example

var instance = timeDelta.create({
  locale: 'en' // default
});

However, the locales/ folder is not currently shipped with the package, so the above code will fail.
This MR fixes this.

[slavafomin]

Hello! Have you tried to use more modern/maintained library? I'm a bit curious why have you selected this slightly outdated (6 years) one :)

[slavafomin]

@jamesdorfman I've dramatically refactored the library today. Please, try to download the latest version and tell me if it works for you. Thanks.

[jamesdorfman]

Hi, I could not find a more modern library to do this.
I just needed to find the difference between two dates, in English (not numerically).
But, if you have others you are aware of that do the same thing, I would happily check them out :)

Thanks for the update! I'll give it a go and let you know

[slavafomin]

I could not find a more modern library to do this.

I see. The good thing is that I've updated it then.

What is your target platform? Are you using it in browser or Node.js?