Outdated documentation.

Hello, I like the concept of this module. When I try following your `README.md` instructions I get an undefined function error

``` javascript
var parser = require("packet").createParser(); // Undefined
var serializer = require("packet").createSerializer(); // Undefined
```

I found that this works, but I don't know how to use it. How can I make a serializer from this?

``` javascript
var packet = require('packet').createPacketizer();
```

Is the documentation outdated?

Thanks.