Consistent ordering and formatting for talk events

Use a consistent format for talk events, with the most recent talk at
the top of the list with the rest in a descending order.

This removes the need to use a `reverse` filter in the events partial.

source/_talks/drupal-vm-generator.md

@@ -12,14 +12,16 @@ video:
   type: youtube
   id: U1pbKAAO2Wo
 events:
-  - name: NWDUG
-    url: http://nwdrupal.org.uk
-    location: Manchester, UK
-    date: 2016-03-08
-  - name: Drupal Bristol
+  -
+    name: Drupal Bristol
     location: Bristol, UK
     url: https://www.drupalbristol.org.uk
     date: 2016-04-02
+  -
+    name: NWDUG
+    url: http://nwdrupal.org.uk
+    location: Manchester, UK
+    date: 2016-03-08
 ---
 
 An short talk about the [Drupal VM Generator][1] project.