Add fingerprinting to locale.json files

[mydea]

We want the locale files (e.g. en.json) to be properly cached by the browser. However, because ember-cli's fingerprinting doesn't work for this case, we need to implement this manually.

The ideal solution would be:

• When generating a new locale.json file, generate it with a random fingerprint (e.g. en-12345.json).
• Automatically save this fingerprint e.g. in the environment.js

E.g.:

// environment.js
var ENV = {
  // ...
  'ember-l10n': { 
    fingerprint: '12345' 
  }
}

[arm1n]

@mydea Isn't this already fixed by #13? If so, please close this issue - thanks!

[mydea]

Yes, I forgot to close this :)