Setting a child of a node to its parent's value fails

[zml2008]

Given an operation such as:

void toList(final ConfigurationNode node) {
  if (!node.isList()) {
    node.appendListNode().from(node);
  }
}

what would be expected is for the contents of node to be moved into a new list child of the node.

What happens instead is something else -- and leads to attached, non-root nodes with a null value, which should not be possible. Initial attempts at changing where nodes are ensured attached in AbstractConfigurationNode.from were unsuccessful -- will need to look into this more.