Bug 214649 [Markers] Allow markerAttributeGroupings and markerGroups to be specified within contentGenerators
With everything at the top level it is hard to see the relation to a contentGenerator and the groups and attribute groupings. These should be sub elements a la menus.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/MarkerContentGenerator.java
private static final String ATTRIBUTE_DEFAULT_MARKER_GROUPING = "defaultMarkerGrouping"; 
	private static final String ATTRIBUTE_VISIBLE = "visible"; 
	static final Object CACHE_UPDATE_FAMILY = new Object();
	private static final String ELEMENT_MARKER_FIELD_FILTER_GROUP = "markerFieldFilterGrouping"; 
	private static final IResource[] EMPTY_RESOURCE_ARRAY = new IResource[0];
	private static final String MARKER_FIELD_REFERENCE = "markerFieldReference"; 
	private MarkerField[] allFields;
	private IConfigurationElement configurationElement;
	private Collection markerTypes;
	private MarkerField[] initialVisible;
	/**
	 * Create a new MarkerContentGenerator
	 * 
	 * @param element
	 */
	public MarkerContentGenerator(IConfigurationElement element) {
		configurationElement = element;