Bug 126839 [DataBinding] IObservable refactoring
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/provisional/databinding/ChangeEvent.java
* @return the change type
	 */
	public int getChangeType() {
		return changeType;
	}
	/**
	 * Returns the value after the change, if available, or <code>null</code>
	 * if the change is a removal from a list.
	 * 
	 * @return the new value, or null
	 */
	public Object getNewValue() {
		return newValue;
	}
	/**
	 * Returns the value before the change, if available, or <code>null</code>
	 * if the change is an addition to a list.
	 * 
	 * @return the old value, or null
	 */
	public Object getOldValue() {
		return oldValue;
	}
	/**
	 * If the updatable is a list, return the position of the changed element,
	 * or POSITION_ALL if more than one element was changed, added or removed.
	 * The return value is unspecified if the updatable is not a list.
	 * 
	 * @return the position of the changed element
	 */