code: async function(library, locale) {
        var t = this;
        var id = locale + ":" + library.getNamespace();
        var translation = t.__translations[id];
        if (!translation) {
          translation = t.__translations[id] = new qx.tool.compiler.app.Translation(library, locale);
          await translation.checkRead();
        } 
        return translation;
      }
docs: Gets the translation for the locale and library, caching teh result.
  @param library
  @param locale
  @returns {Promise(translation)}