Style past-events with no photo to take up full width of slider

* When there's no photo, add no-photo class to past-event article
* Style past-event details to take up full width when there is no photo

Author: estebistec

pythonkc_site/static/screen.css

@@ -125,6 +125,9 @@ h3{
     width: 400px;
     float: left;
 }
+.past-event.no-photo .details {
+    width: 910px;
+}
 .past-event .event-photo {
     float: left;
     width: 500px;

pythonkc_site/templates/index.html

@@ -53,7 +53,7 @@ <h1>Past Events</h1>
       </div>
       <div id="evt-wrapper">
         {% for event in past_events %}
-        <article class="past-event">
+        <article class="past-event{% if not event.photos.0.url %} no-photo{% endif %}">
           <div class="details">
             <header>
               <h1><time datetime>{{ event.time|date:"F j, Y" }}</time></h1>