output event name for delegateListeners, for better debug

So when you forgot to implement a listener method:

```
    listen:
        'addedToDOM':   'someNoneExistingMethod'
```

instead of

```
Uncaught Error: View#delegateListeners: undefined must be function 
```

We saw:
```
Uncaught Error: View#delegateListeners: listener for "addedToDOM" must be function 
```