Bug 184755 [DataBinding] internal tree content provider does not work
I broke the tree content providers while trying to update them to use TreePaths. It would be good to have a working implementation again...
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/internal/viewers/OrderedTreeNode.java
* @return a parent node, or <code>null</code>
	 */
	public Object getParent() {
		return parent;
	}
	/**
	 * @return the set of known parent nodes
	 */
	public Set getParents() {
		if (parents == null) {
			if (parent == null) {
				return Collections.EMPTY_SET;
			}
			return Collections.singleton(parent);
		}
		return parents;
	}
	/**
	 * Called when the child set changes. Should not be called directly by the
	 * viewer.
	 */
	public void handleListChange(ListChangeEvent event) {
		boolean shouldHavePendingNode = children.isEmpty()
				&& children.isStale();
		List removals = new ArrayList();
		ListDiffEntry[] differences = event.diff.getDifferences();
		for (int i = 0; i < differences.length; i++) {
			ListDiffEntry diffEntry = differences[i];
			if (diffEntry.isAddition()) {
				contentProvider.insert(element, diffEntry.getElement(),