3d Editor and Debugger?

[haydenflinner]

Got this working tonight through the magic of Ursina. Read-only black and white view for today. Plans:

1. Click a test case to comment out all other test cases, which will dovetail with:
2. Hover mouse cursor over a symbol to show a little side screen with just the output of that ? output in it. Or perhaps a better/more-visceral visualization of the stack.