Make contour maps available in 3D view

[magnesj]

• make the contour map available for visualization in a 3d view
• create a new collection in 3d view ContourMapInViewCollection
• create a view wrapper object for contour maps
• allow contour map data to be visualized using colors
• allow contour map polygon lines to be displayed in 3d view
• add option to project contour map polygon lines onto the visible geometry in the 3d view