toString() q params, missing &

```
URN_8141 urn = URN.rfc8141().parse("urn:XY:ORDER:111111?=x=y&z=c");
System.out.println(urn.toString());
System.out.println(urn.toURI().toString());
```

```
urn:LB:ORDER:111111?=x=yz=c
urn:LB:ORDER:111111?=x=yz=c
```

where are the `&` separators?

I'm running 2.0.1....