Update Redirecting section in Routing guide

 * The `redirect` hook is now deprecated in favor of `beforeModel` and `afterModel`.
Add back and bring up-to-date filtering section in Redirecting guide
Add section headers to Redirecting guide
Note that the redirect hook can be used the same as afterModel can
Merge pull request #768 from balinterdi/update-redirecting-guide

Update Redirecting section in Routing guide