Bug 126839 [DataBinding] IObservable refactoring
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/beans/ListenerSupport.java
addPropertyChangeListenerMethod = target.getClass().getMethod(
					"addPropertyChangeListener", 
					new Class[] { PropertyChangeListener.class });
		} catch (SecurityException e) {
			
		} catch (NoSuchMethodException e) {
			
		}
		if (addPropertyChangeListenerMethod != null) {
			try {
				addPropertyChangeListenerMethod.invoke(target,
						new Object[] { listener });
				elementsListenedTo.add(new IdentityWrapper(target));
				return;
			} catch (IllegalArgumentException e) {
				
			} catch (IllegalAccessException e) {
				
			} catch (InvocationTargetException e) {
				
			}
		}
	}
		
	/**
	 * Add listeners for new targets (those this instance of<code>ListenerSupport</code> does not 
	 * already listen to),
	 * Stop to listen to those object that this instance listen to and is one of the object in targets 
	 * 
	 * @param targets