Add an index for event_type on info_request_events

Selecting request events for a particular body is slow
because we need to filter the events by event_type and
don't currently have an index on that field. This should
speed that up. Closes #1709
Try some eager loading to speed up body_request_events
Merge branch 'issues/1709-api-controller-speed' into rails-3-develop
Merge branch 'issues/1709-eager-load-for-api-speed' into rails-3-develop