context.events should use dot notation

Ideally we'd be able to do something like this:

``` python
event_names = [event.action.name for event in events]
if 'Approve Taxes' in event_names and 'Approve Parking' in event_names:
change_state('Approved')
```

But currently we have to use:

``` python
event_names = [event['action']['name'] for event in events]
```

Not a huge deal, just easier to write.
Related to #20