Improvements to ModelDiagram.
Improvements to ModelDiagram.

mdittmer/foam,mdittmer/foam,foam-framework/foam,foam-framework/foam,mdittmer/foam,foam-framework/foam,jlhughes/foam,jlhughes/foam,mdittmer/foam,foam-framework/foam,jlhughes/foam,jlhughes/foam,foam-framework/foam