Bug 158778 [Viewers] request for remove(parent, index) API on tree viewer
3.3 It would be helpful to have a 'remove(Object parent, int index)' method on the tree viewer to complement that 'replace(...)' and 'setChildCount(...)' APIs. The debug platform requires such a method to implement filtering in virtual tree views. Rather than performing a 'replace/remove' based on elements, the content provider can make one atomic call to remove an element at a specific index.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
* (non-Javadoc) Method declared in AbstractTreeViewer.
	 */
	protected Item[] getSelection(Control widget) {
		return ((Tree) widget).getSelection();
	}
	/**
	 * Returns this tree viewer's tree control.
	 * 
	 * @return the tree control
	 */
	public Tree getTree() {
		return tree;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.AbstractTreeViewer#hookControl(org.eclipse.swt.widgets.Control)
	 */
	protected void hookControl(Control control) {
		super.hookControl(control);
		Tree treeControl = (Tree) control;
		treeControl.addMouseListener(new MouseAdapter() {
			public void mouseDown(MouseEvent e) {
				treeViewerImpl.handleMouseDown(e);
			}
		});
		if ((treeControl.getStyle() & SWT.VIRTUAL) != 0) {
			treeControl.addDisposeListener(new DisposeListener() {
				public void widgetDisposed(DisposeEvent e) {
					treeIsDisposed = true;