Add composer.json to support composer installation

If you add this composer.json .

People can add a composer.json in root and add

```php
{
    "minimum-stability": "dev",
    "require": {
       "ryancramerdesign/process-export-profile": "dev-master"
    }
}
```

If `"minimum-stability": "dev",` is added it will check whether the package is stable of type. 

```bash 
php composer.phar update
```

Thoughts ?