tutorial on passing parameter in callback

Another tutorial I think students will greatly benefit from is being able to pass a parameter in a callback. I am able to teach this in the classroom but it becomes a tad difficult to explain this via slack at midnight to a student.

```
btn_roomGenerator.mousePressed(_ => {
generateRoom.call(this, randRoom);
console.log('generated room');
});
```

maybe this could be a tut on call(), apply(), and bind() ... ?