Bugfix/28 compute redirect to location signature

@nsimmons, @qq99 for review

I realize that this is ugly, but since we're using `alias_method_chain` I didn't see another option.

Rails 4.2+ has a different signature for this method, so we need to support two versions of `_compute_redirect_to_location_with_xhr_referer`. 

See <https://github.com/rails/rails/blob/001e600619c7ec5d7535e47c5900bcad259de3f8/actionpack/lib/action_controller/metal/redirecting.rb> for the updated version.

Fixes #28