Orbit/arcball camera

[aforren1]

This is if we end up using ratcave for drawing things -- either that, or we fix the camera/change the view depending on the trial.

[aforren1]

Desirable controls:

• rotate around a center point (hold mouse button + drag)
• shift center point (hold another mouse button + drag)
• zoom in/out (scroll wheel)
• reset view to default

[aforren1]

Lower priority now -- I think we'll get away with 2d graphics.