Use an object of promises in Promise.all()

So basically the idea is the same as [Dojo](http://dojotoolkit.org/reference-guide/1.10/dojo/promise/all.html#id4) where we can pass an object to Promise.all() and the results are paired with their keys. With this way I can identify where the result came from.

Instead of an array we use and object
```actionscript
Promise.all({
  tableA: Promise.when(queryTask1.execute(query)),
  tableB: Promise.when(queryTask2.execute(query))
}).then(onTaskResult).otherwise(onTaskFault);
```

Then we can use the object keys to identify the results
```actionscript
private function onTaskResult(results:Object):void {
  for (var key:String in results) {
    ...
  }
}
```