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/views/markers/internal/MarkerSupportRegistry.java
for (int i = 0; i < extensions.length; i++) {
			IExtension extension = extensions[i];
			processExtension(tracker, extension, groupingEntries,
					entryIDsToEntries, attributeMappings);
		}
		postProcessExtensions(groupingEntries, entryIDsToEntries,
				attributeMappings);
		tracker.registerHandler(this, ExtensionTracker
				.createExtensionPointFilter(point));
	}
	/**
	 * Process the extension and register the result with the tracker. Fill the
	 * map of groupingEntries and attribueMappings processed for post
	 * processing.
	 * 
	 * @param tracker
	 * @param extension
	 * @param groupIDsToEntries
	 *            Mapping of group names to the markerGroupingEntries registered
	 *            for them
	 * @param entryIDsToEntries
	 *            Mapping of entry ids to entries
	 * @param attributeMappings
	 *            the markerAttributeGroupings found
	 * @see #postProcessExtensions(Map, Map, Collection)
	 */
	private void processExtension(IExtensionTracker tracker,
			IExtension extension, Map groupIDsToEntries, Map entryIDsToEntries,
			Collection attributeMappings) {
		IConfigurationElement[] elements = extension.getConfigurationElements();