Add missing dependency for transpiling es6

package.json

@@ -19,8 +19,8 @@
     "gulp-cached": "^1.1.1",
     "gulp-chmod": "^2.0.0",
     "gulp-concat": "^2.6.1",
-    "gulp-if": "^2.0.2",
     "gulp-git": "^2.8.0",
+    "gulp-if": "^2.0.2",
     "gulp-livereload": "^4.0.0",
     "gulp-plumber": "^1.2.0",
     "gulp-pug": "^4.0.1",
@@ -30,6 +30,7 @@
     "gulp-uglify-es": "^1.0.4",
     "jest": "^23.6.0",
     "minimist": "^1.2.0",
+    "vinyl-buffer": "^1.0.1",
     "vinyl-source-stream": "^2.0.0"
   },
   "dependencies": {