[NONE] Remove ILayoutModel, rename DefaultLayoutModel to LayoutModel.
[454146] Move sugiyama-specific abstractions into the SugiyamaLayoutAlgorithm class.
[454148] Move ExpandCollapseManager to SpaceTreeLayoutAlgorithm.
[NONE] Remove deprecated interface.
[NONE] Move layout property constants to layout helper.

 - Rename LayoutPropertiesHelper to LayoutProperties
 - Remove ILayoutProperties