Exomoons

[rodluger]

Exomoons can now be modeled with the code, but there is still a small issue with the NBody integrator: my Keplerian subgrid isn't working, so the NBody code has to be run with timesteps equal to the observation cadence. Not a dealbreaker, but it's currently slowing down the code.

The issue is that when I try to get osculating orbital elements for the moon for the subgrid, REBOUND spits out nonsense. I'm sure there's a way to do it, but it's not documented well.