Fix query string to params, pass routing options

This is a proof of concept without tests for fixing two things:

- Fix query extraction of query string parameters to `params` #351
- Pass the full path to controller actions (see discussion of #319). My solution: just pass the whole routing options as second parameter. This used to be the previous controller name. I think it’s okay to make a breaking change here. The previous controller name is now added to the routing options, so it’s easy to upgrade.

Specifically:

- Pass routing options instead of previous controller name to controller actions
- Add previousControllerName to routing options
- Separate query string from the path and add it to the routing options
- Route#extractQueryParams uses options.queryString or location.search
- Cleanup and comments for consistency

Feel free to comment / make changes / add tests.