First chapter exercises.

Hey @fabioyamate, just finished the first chapter's exercises. Could you take a look?
I'm going to try to use the term "function application" because it seems to be the proper way to call it. Normally, we would say: "call this function", but the book uses the term application.

In Javascript we can do:

```javascript
fn.apply(null, arg1, arg2)
```

There is a `.call` for functions in JS, but it requires an array of arguments. `fn.call(null, [arg1, arg2])`

Similar in clojure: `(apply + (range 10))`