Update composer.json

Added package name in order to make the package installable.

By adding a ***name*** value, you allow developers to bootstrap the entire application installation process directly from composer, via the create-project command; e.g. ...

> composer create-project laravel/laravel:dev-develop path/to/laravel-4-app

This replaces the separate step of having to download and extract a zip file, or clone the application repository.

I'm still learning proper usage of composer, so there may be a better way to enable the above, but I only had success once I added the following to my global composer config file (example assumes you accept my addition to the composer.json file) ...

```json
{
    "config": {

    },
    "repositories": {
        "laravel": {
            "type": "vcs",
            "url": "http://github.com/laravel/laravel"
        }
    }
}
```