or() doesn't clean up __rqlId attributes

In js-array.js, the or() function attempts to clean up its temporary '__rqlId' attributes using:

```
// cleanup markers
for(var i = 0, l = items.length; i < l; i++){
delete items[idProperty];
}
```

This should be:

```
// cleanup markers
for(var i = 0, l = items.length; i < l; i++){
delete items[i][idProperty];
}
```

With enough objects and frequent enough queries, this can lead to a substantial memory leak.