Bug 315281 update copyrights for 3.6
bundles/org.eclipse.core.databinding.property/src/org/eclipse/core/internal/databinding/property/set/SimplePropertyObservableSet.java
additions.removeAll(set);
		if (additions.isEmpty())
			return false;
		SetDiff diff = Diffs.createSetDiff(additions, Collections.EMPTY_SET);
		updateSet(set, diff);
		return true;
	}
	public boolean removeAll(Collection c) {
		getterCalled();
		if (c.isEmpty())
			return false;
		Set set = getSet();
		if (set.isEmpty())
			return false;
		Set removals = new HashSet(c);
		removals.retainAll(set);
		if (removals.isEmpty())
			return false;
		SetDiff diff = Diffs.createSetDiff(Collections.EMPTY_SET, removals);
		updateSet(set, diff);
		return true;
	}
	public boolean retainAll(Collection c) {
		getterCalled();
		Set set = getSet();
		if (set.isEmpty())
			return false;
		if (c.isEmpty()) {
			clear();
			return true;