Fixes for https://github.com/krakenjs/generator-kraken/issues/115

- [x] Only add .bowerrc when a templateModule is picked, this is a separate prompt option now
- [x] Middleware for serverError and fileNotFound will not be added by default, as they assume templates with error messages today
- [x] Controllers will just do `res.json` when no templateModule selected
Since it's still—generally—being requested as html, should we do something like:
``` js
res.send('<code><pre>' + JSON.stringify(model, null, 2) + '</pre></code>');
```