Use less memory to build translation files (#6070)

* Change languages build to use less memory

Add graceful-fs so no ned to worry about fs limits

* Specify encoding for fs.readFile

Use eachLimit since graceful-fs handles that now

src/image.js

@@ -120,9 +120,7 @@ image.size = function (path, callback) {
 };
 
 image.convertImageToBase64 = function (path, callback) {
-	fs.readFile(path, function (err, data) {
-		callback(err, data ? data.toString('base64') : null);
-	});
+	fs.readFile(path, 'base64', callback);
 };
 
 image.mimeFromBase64 = function (imageData) {