List lister helper

I have not tested this code yet because of how the develop branch is not yet in a usable state, but as I may be missing for a few days I thought I should get it here in case you want to give it a try.

To use:
```
LIST PARTS IN FOO.
PRINT FOO. // terse
PRINT FOO:DUMP(). // verbose
```

with these longer string builders, it took me a bit of time to understand what the different parts where. So i extracted the intent calculation outside the loop and gave it a name.