Add a new "broadcast_event_object" method to accept an obejct not a string

I probably want this to be the default, (replacing broadcast_event
entirely, or perhaps renaming it to broadcast_event_string if there
are any users that do need to stick around).

With cases like this, I do wish I was using a type safe language to
avoid the confusion that comes with "Does this function want an object
or a string representation of that object?".