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/CachedMarkerBuilder.java
return filters;
	}
	/**
	 * Return the categories for the receiver.
	 * 
	 * @return MarkerCategory[] or <code>null</code> if there are no
	 *         categories.
	 */
	MarkerCategory[] getCategories() {
		if (building) {
			return null;
		}
		return categories;
	}
	/**
	 * Return the group used to generate categories.
	 * 
	 * @return MarkerGroup or <code>null</code>.
	 */
	MarkerGroup getCategoryGroup() {
		return categoryGroup;
	}
	/**
	 * Return a new instance of the receiver with the field
	 * 
	 * @return MarkerComparator
	 */
	MarkerComparator getComparator() {
		if (comparator == null) {
			MarkerField field = null;