feat: Add XO config

Author: finom

package.json

@@ -66,6 +66,7 @@
     "eslint-config-eslint": "^3.0.0",
     "eslint-config-google": "^0.6.0",
     "eslint-config-standard": "^6.2.0",
+    "eslint-config-xo": "^0.17.0",
     "extract-text-webpack-plugin": "^1.0.1",
     "ghooks": "^1.3.2",
     "html-webpack-plugin": "^2.22.0",