specs_messenger

message passing component for specs

```rust let mut world = World::new();

let mut dispatcher = SpecsBundler::new(&mut world, DispatcherBuilder::new()) .bundle(MessengerBundle::::new()).unwrap() .build();

let entity0 = world .create_entity() .with(Messenger::::new()) .build();

let entity1 = world .create_entity() .with(Messenger::::new()) .build();

let entity2 = world .create_entity() .with(Messenger::::new()) .build();

{ let mut messengers = world.write_storage::>();

messengers
    .get_mut(entity0)
    .unwrap()
    .send(entity1, "Direct".into());

messengers
    .get_mut(entity2)
    .unwrap()
    .broadcast("Broadcast".into());

}

dispatcher.dispatch(&mut world.res); ```