Walls: Don't connect to group:cracky
Walls: Don't connect to group:cracky

the ```group:cracky``` group contains all sorts of odds and ends
nodes that we shouldn't connect to. There are a few nodes that
walls now no longer connect to, that probably should get
```group:stone``` added, or something similar, though.

evrooije/beerarchy,evrooije/beerarchy,evrooije/beerarchy