Add ES2015+ files to JSHint ignored list

Gruntfile.js

@@ -103,6 +103,7 @@ module.exports = function(grunt) {
         '!js/Mp3LameEncoder.min.js',
         '!js/libsignal-protocol-worker.js',
         '!js/components.js',
+        '!js/modules/**/*.js',
         '!js/signal_protocol_store.js',
         '_locales/**/*'
       ],

js/modules/auto_orient_image.js

@@ -1,5 +1,3 @@
-/* jshint ignore:start */
-
 const loadImage = require('blueimp-load-image');
 
 // File | Blob | URLString -> LoadImageOptions -> Promise<DataURLString>

js/modules/types/attachment.js

@@ -1,4 +1,3 @@
-/* jshint ignore:start */
 
 const dataURLToBlob = require('blueimp-canvas-to-blob');