[ddahlen]

Final edits of a paper at the moment, aim to submit next week. Perturbers are easy to add, though a little poorly documented at the moment. Additional physics right now are J2 of jupiter/sun/earth, and GR corrections for the sun and jupiter.

Biggest speed gain is that I have a custom SPICE reader that is multi-core friendly (I re-implemented a lot of the SPICE standard in rust), and it is used as the source for planet positions. Being able to skip planet integration leads to massive speedups.