IGraphModelFactory: extended meet testing requirements
Aligner, GraphSceneFacade: use AffectedEdges found by Walker
cleanup
Refactoring EntityGraphFactory to  BasicTestGraphFactory<TItem, TEdge> to use Expamples with every IGraph<TItem, TEdge>
refactor to use BasicTestGraphFactory<TItem,TEdge>
rename TestGraphFactory => SampleGraphFactory
GraphSceneFactory: refactored out of SceneFactory
cleanups and minor changes
more GraphTest cleanups