* Added new high order symplectic integrators from Wisdom et al. (1996) and Laskar & Robutel (2001). The implementation of these integrators are discussed in Rein, Tamayo & Brown (2019).
* Implemented new bit-wise comparison functions for simulations. Python syntax is simply sim1==sim2.
* Fixed a bug in IAS15 which prevented a restarted simulation to reproduce the original simulation exactly.