Added sg_message_id to all event types.  Added sg_event_id to "open" and "click" event types.
Added sg_message_id to all event types.  Added sg_event_id to "open" and "click" event types.

nysenate/SendgridStatsAccumulator,nysenate/SendgridStatsAccumulator,nysenate/SendgridStatsAccumulator,nysenate/SendgridStatsAccumulator