I've opted for a slightly shorter name for PTR owner names
The result looks like this:
```
catz. 0 IN SOA invalid. invalid. 23 60 10 1209600 0
zid-000002.zones.catz. 0 IN PTR 2.0.192.in-addr.arpa.
zid-000001.zones.catz. 0 IN PTR example.net.
zid-000003.zones.catz. 0 IN PTR jpmens.net.
zid-000004.zones.catz. 0 IN PTR tcp53.ch.
catz. 0 IN NS invalid.
version.catz. 0 IN TXT "2"
```
