Layout not reset if unhandled error thrown in route code.

[wassupduck]

When an error is thrown in the route code and is not handled the layout is never reset.

Scenario:

1. Add ajax route that dies to an existing Dancer2 app that uses a layout.
2. Navigate around app from browser - layout and content rendered.
3. Send ajax request to erroneous ajax route.
4. Navigate around app from browser - content will be rendered, layout will not.

Example erroneous ajax route:

ajax '/error' => sub {
  die 'houston we have a problem!';
};

[konsumate]

I've tried a fix in #4 - please review or enhance.