Exposes total items

Exposes the totalItems in the response, it's something that should be present in the system by default.
That won't work you can try it out, if you don't pass the scope, you can't use it.

I did this 

```
<ad-table-ajax table-name="table" on-data-loaded="callback($success, $response);"></ad-table-ajax>
```

```
$scope.callback = function ($success, $response) {
 console.log(arguments);
};
```

It won't get called without the scope in the callback, but in your function, you don't get the scope, 
You will get

$success, $response, CALLEE, CALLER

If you know of a way to make it work without it, feel free to modify it.