data: Add access to route metadata in the templating data. It's available under `route`. Also, rename `slug` to `rel_url`, because it's confusing when `slug` could be the route metadata of the same name as provided by the default page source. The old `slug` is still there for backwards compatibility though.

{% extends "default.html" %}

{% block content %}
<div class="container">
    <section class="col-md-8">
    {{ content|safe }}
    </section>
    <aside class="col-md-4">
        {% include 'inc/family-sidebar.html' %}
    </aside>
</div>
{% endblock %}