Bug 161401 [Viewers] Tweak ColumnViewer-API
- Rename getRowPart(Point point) => getViewerRow() - Rename getCell(Point point) => getViewerCell() - Rename setViewerColumn(final int columnIndex, ViewerColumn viewer) => setupEditingSupport - Make setupEditingSupport() private no one from external needs to use this API to set the EditingSupport for an ViewerColumn
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
* @since 3.3
	 */
	public void setHasChildren(Object elementOrTreePath, boolean hasChildren) {
		if (internalIsInputOrEmptyPath(elementOrTreePath)) {
			if (hasChildren) {
				virtualLazyUpdateChildCount(getTree(), getChildren(getTree()).length);
			} else {
				setChildCount(elementOrTreePath, 0);
			}
			return;
		}
		Widget[] items = internalFindItems(elementOrTreePath);
		for (int i = 0; i < items.length; i++) {
				TreeItem item = (TreeItem) items[i];
				if (!hasChildren) {
					item.setItemCount(0);
				} else {
					if (!item.getExpanded()) {
						item.setItemCount(1);
					}
				}
		}
	}
	/**
	 * @param widget
	 * @param i
	 */
	private void virtualLazyUpdateWidget(Widget widget, int index) {
		if (contentProviderIsTreeBased) {
			TreePath treePath;