Added original callback to the before filter arguments

[synthomat]

I didn't find a solution to call the original callback from the before-filter to do a custom routing.

[boazsender]

Thanks for the PR @synthomat and @cobrainer.

I just ran this and didn't see any regressions. Can you add a test case for doing this to test/backbone.routefilter_test.js?

Thanks again!

[boazsender]

@synthomat & @cobrainer, can you also document this behavior in the README.md.

Thank you.

[boazsender]

I'm also curious about your use case for this @synthomat & @cobrainer. I was just taking a pass at testing/documenting this feature, and can't come up with a use case.

[synthomat]

@boazsender is there another way to modify the routing chain with some logic?

However, I think I followed a wrong approach with preparing sub-layouts based on the routing chain :-/