Karma: Added command to list top5 karmas.

Signed-off-by: Jakub Novak <jakub.novak@gmail.com>
I suppose you could do

```python
for i, (k, v) in enumerate(karmees):
    print i, k, v
```

But in the end you'd still need to increase the position variable by one.

This way, it is pretty obvious and I decided to rather merge this than fight with @JakubNvk.

That being said, feel free to submit a PR!