Remove unused structure
ephemerisHybridFromCartesian can take sim time directly
Store JPL ephemeris inside GravBody. Breaks everything for some reason.
Fix for issue from last commit; Sun's all-0 JPL data was causing NaNs in a couple of places, this is a hacky fix for now.
Compute grav body positions from ephemeris every time
Actually update the positions of the bodies from the ephemeris
Change game start date
WIP towards picking points on orbits
Pick the point on the player ship's orbit closest to the mouse pointer, and draw a point there
Fix julian date calculation to include fractional seconds.

Starting ship seems stable up to 8192x timestep (for what frame time?)
Cap the maximum simulation step and run multiple steps in a frame if necessary.

This seems good enough to get up to the kind of time accelerations we should expect to see in-game.
Release configuration (commented out)
notes
Display the true anomaly for the highlighted point on the orbit next to the mouse cursor.
Calculate and show the time for the maneuver node. Currently gives NaN everywhere on hyperbolic orbits
Fix time calculation for hyperbolic orbits
WIP extract and refactor maneuver node code
orCamera: make methods const
orRender: compute screenFromWorld matrix earlier
WIP