Preserve trailing slash in URL path - Fixes #218

Fixes the issue described in #218.

The URI string that gets saved to the `X-XHR-Current-Location` header has been run through the **ActionDispatch::Journey::Router::Utils.normalize_path()** filter, which strips the trailing slash.  This commit implements that filter on the client side (on document.location.pathname) so we can accurately check to see if the request was redirected.  As a result, clicking a link to `/path/` no longer leads to the URL being changed to `/path`.