Move custom-locales.js to static/js/lib

So it can be loaded ahead of time and cached. Also remove the json since it's being loaded outside of react now, and put it into the js file directly.

src/lib/render.jsx

@@ -2,17 +2,11 @@ var ReactDOM = require('react-dom');
 var ReactIntl = require('react-intl');
 var IntlProvider = ReactIntl.IntlProvider;
 
-var customLanguages = require('./custom-locales.json');
-
 var render = function (jsx, element) {
     // Get locale and messages from global namespace (see "init.js")
     var locale = window._locale;
     var messages = window._translations[locale];
 
-    if (customLanguages[locale] !== undefined) {
-        ReactIntl.addLocaleData(customLanguages[locale]);
-    }
-
     // Render component
     var component = ReactDOM.render(
         <IntlProvider locale={locale} messages={messages}>