refactor TriggerBatch's Event.Data str->interface (#50)
refactor TriggerBatch's Event.Data str->interface (#50)

- it refactors TriggerBatch's API regarding Event.Data to be consistent with the Trigger's API , moving from a `string` type to a `interface{}` type. This allows any matching type to be passed in as a Payload.
pusher/pusher-http-go