Provide navigation through steps

From comments on the Install Drupal locally step, now deleted, (http://learndrupal.org/lesson/8daa1222-481d-fc54-a9bf-9d9ccc1ae702) it would be nice to have forward and back links on the lessons so that you can proceed to the next step in a lesson without having to go back to the main page to find the link for the next step.