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- Added different options for performing the necessary sort in the
approximate version of the algorithm: mergesort, quicksort, timsort,
as well as a parallel mergesort (which is, however, not very
efficient).
- Added option to add an arbitrary external force F(x,t) to the
approximate version of the algorithm.
- Added an example of using wendy to generate a phase-space spiral
similar to that observed by Gaia, through a simple perturbation of
the Galactic disk (examples/GaiaPhaseSpaceSpiral.ipynb).