BUG: Not getting styles in prod / dist mode.

`npm run build` fails to include critical CSS:

`npm run build`:

```
data = {
  "main": "surge2015.0.0.1.js",
  "isDev": false
}
```

`npm run dev`:

```
data = {
  "css": "app.js.map",
  "main": "app.js",
  "isDev": true
}
```

Wow, I messed that up.

/cc @kenwheeler
