list sharing implemented w. passing UTs & FTs; changes to apps.dashboard.urls, .models, .views & .tests.test_views to accomodate; functional_tests.test_sharing also ensures sharing visible in UX; templates/apps/dashboard/list.html & /my_lists.html updated with django templating & for loops

src/templates/apps/dashboard/my_lists.html

@@ -9,4 +9,10 @@
             <li><a href="{{ list.get_absolute_url }}">{{ list.name }}</a></li>
         {% endfor %}
     </ul>
+    <h3>Lists shared with me</h3>
+    <ul>
+        {% for list in owner.shared_lists.all %}
+            <li><a href="{{ list.get_absolute_url }}">{{ list.name }}</a></li>
+        {% endfor %}
+    </ul>
 {% endblock content %}