Uncaught ReferenceError: process is not defined

Just a clean install

```
npm install -g vue-cli
vue init webpack project
cd project
npm install
npm run dev
```

process.env.NODE_ENV entities are not replaced by 

```
new webpack.DefinePlugin({
   'process.env': config.dev.env
}),
```

node -v
v6.2.1

possibly related
https://github.com/webpack/webpack/issues/2312
