Bug 165368 [Viewers] TreePath.getParentPath() should return empty path
TreePath.getParentPath() specifies that it returns null for an empty path. However, it also returns null for a one element path. I think it should return the empty path for a one element path, to be consistent with an empty path representing a root element in a tree.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreePath.java
}
	/**
	 * Returns the last element in this path.
	 * 
	 * @return the last element in this path
	 */
	public Object getLastSegment() {
		if (segments.length == 0) {
			return null;
		}
		return segments[segments.length - 1];
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	public boolean equals(Object other) {
		if (!(other instanceof TreePath)) {
			return false;
		}
		return equals((TreePath) other, null);
	}
	/**
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#hashCode()
	 */
	public int hashCode() {
		if (hash == 0) {