chore(env.t): expose basic env.t() implementation for 'en' so mobile app

can use the function

src/middleware.js

@@ -255,3 +255,10 @@ module.exports.locals = function(req, res, next) {
     next();
   });
 }
+
+module.exports.enTranslations = function(stringName, vars){
+  var language = {code:'en'};
+  var string = translations[language.code][stringName];
+  if(!string) return _.template(translations[language.code].stringNotFound, {string: stringName});
+  return vars === undefined ? string : _.template(string, vars);
+};