A dependency graph transformer that creates a topological sorting of the conflict ids which have been assigned to the
 dependency nodes. Conflict ids are sorted according to the dependency relation induced by the dependency graph. This
 transformer will query the key 
TransformationContextKeys.CONFLICT_IDS in the transformation context for an
 existing mapping of nodes to their conflicts ids. In absence of this map, the transformer will automatically invoke
 the 
ConflictMarker to calculate the conflict ids. When this transformer has executed, the transformation
 context holds a 
List<Object> that denotes the topologically sorted conflict ids. The list will be stored
 using the key 
TransformationContextKeys.SORTED_CONFLICT_IDS. In addition, the transformer will store a
 
Collection<Collection<Object>> using the key 
TransformationContextKeys.CYCLIC_CONFLICT_IDS that
 describes cycles among conflict ids.