BUG: imports in domain-atomistic.py should be updated 

Hej Atomistic-developers,

there is a bug in domain-atomistic.py:
```
from emmo import World
from emmo.utils import  write_catalog
```

it should be updated to 
```
from ontopy import World
from ontopy.utils import write_catalog

```
I guess :) - at least then it is working at my place.... Thanks for fixing !