s/lang/locale

 * Deprecated moment.lang(), moment.langData(), moment#lang, and
 duration#lang

 * Added moment.locale(), moment.localeData(), moment#localeData, and
 druation#localeData

 * Added moment.defineLocale() that defines a locale but doesn't set it
 as the global locale (#1750)

 * Removed the hack in the language concatenator that set the language
 to English.

 * Refactored internal code to use moment#localeData instead of local
 functions, and set the language directly on the moment instance at
 creation.

 * Moved all the files and changed the build scripts so that everything
 lives is named "locale" instead of "lang", e.g. the locale files under
 the "locale" directory.

 * I did *not* include build-generated changes like component.json and
 the concated locale files, but I did inspect them to see that they look
 right. But I did remove the old ones wherever they won't be named correctly in the future.
```javascript
test.equal(require('../../lang/bg'), 'bg', "module should export bg");
```

You're talking about this line? It should become
```javascript
test.equal(require('../../lang/bg').abbr(), 'bg', "module should export bg");
```

or similar. If that is the case it should be a not-so-complicated vim-macro. Also I'm not sure why we have this test anyway. What exactly is the point (except loading the file with moment), but the file should already be loaded because of the other tests. You should be able to just drop it.