Bug 218884 [DataBinding] Add API: WorkbenchObservables
... for things like listening to ISelectionService
bundles/org.eclipse.core.databinding.observable/src/org/eclipse/core/databinding/observable/Observables.java
* 
	 * @param realm
	 *            the realm of the returned set
	 * @param set
	 *            the set to wrap in an IObservableSet
	 * @param elementType
	 *            the element type of the returned set
	 * @return an observable set backed by the given set
	 * @since 1.1
	 */
	public static IObservableSet staticObservableSet(Realm realm, Set set,
			Object elementType) {
		return new ObservableSet(realm, set, elementType) {
			public synchronized void addChangeListener(IChangeListener listener) {
			}
			public synchronized void addStaleListener(IStaleListener listener) {
			}
			public synchronized void addSetChangeListener(ISetChangeListener listener) {
			}
		};
	}
	/**
	 * Returns an observable value that contains the same value as the given
	 * observable, and fires the same events as the given observable, but can be
	 * disposed of without disposing of the wrapped observable.
	 * 
	 * @param target
	 *            the observable value to wrap
	 * @return a disposable proxy for the given observable value.
	 * @since 1.2