Bug 317954 Version deltas file so that incompatible changes will be ignored
The deltas file needs to be versioned so that incompatible changes will be discarded allowing the workbench to be constructed as if there were no deltas in existence.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/XMLModelReconciler.java
}
	/**
	 * Returns whether this feature should be persisted.
	 * 
	 * @param featureName
	 *            the name of the feature
	 * @return <code>true</code> if this particular feature should be persisted, <code>false</code>
	 *         otherwise
	 */
	private static boolean shouldPersist(String featureName) {
		
		return !featureName.equals(UIELEMENT_PARENT_ATTNAME)
				&& !featureName.equals(PARTDESCRIPTORCONTAINER_DESCRIPTORS_ATTNAME);
	}
	private static Collection<EStructuralFeature> collectFeatures(
			Collection<EStructuralFeature> features, EClass eClass) {
		features.addAll(eClass.getEStructuralFeatures());
		for (EClass superType : eClass.getESuperTypes()) {
			collectFeatures(features, superType);
		}
		return features;
	}
	private static Collection<EStructuralFeature> collectFeatures(EObject object) {
		return collectFeatures(new HashSet<EStructuralFeature>(), object.eClass());
	}
	private static boolean isUnset(Element element) {
		return UNSET_ATTVALUE_TRUE.equals(element.getAttribute(UNSET_ATTNAME));
	}
}