Enhances comments, coding standards and readability

I think that's just the class parameter being discussed there.
I've never used the class argument, but I use this function a lot to verify the type/subtype

Don't you think that:

```
if (elgg_instanceof($object, 'object', 'blog')) {
```

Is more readable than

```
if (($object instanceof ElggObject) && ($object->getSubtype() == 'blog')) {
```