convert gulpfile into ES6+

package.json

@@ -19,7 +19,8 @@
     "lodash": "^3.9.1"
   },
   "devDependencies": {
-    "babel": "^5.6.14",
+    "babel": "^5.8.23",
+    "babel-core": "^5.8.25",
     "babel-eslint": "^4.1.3",
     "babelify": "^6.1.1",
     "browser-sync": "^2.9.4",
@@ -29,7 +30,7 @@
     "eslint-config-airbnb": "0.0.9",
     "eslint-plugin-react": "^3.4.2",
     "exorcist": "^0.4.0",
-    "gulp": "~3.8.1",
+    "gulp": "3.9.0",
     "gulp-autoprefixer": "1.0.1",
     "gulp-duration": "0.0.0",
     "gulp-inject": "^3.0.0",