Undid the ancient confusion of mapping the 2D x-y plane to a left-handed coordinate x-z plane. It now uses a right-handed frame and draws directly to the x-y plane.
Added (optional) camera names.
Cameras can report their current projection mode (orthographic vs perspective) and write out their XML representation.
Updated all the examples to use the new info (z-up flag and camera names -- at least for circleV.xml).
Provided const axis to the spatial query and its obstacles.
Modifications to the visualization system