Body changes.
Testing.
Oblateness on massless.
Enum.
Change constructor and factory.
Callers.
Renaming.
Benchmark numbers.
Lint.
After egg's review.
Reworded.
Merge pull request #184 from pleroy/Benchmarks

Add a parameter to control the accuracy of the solar system model, and use it to benchmark different configurations
Merge.
Before test restructuring.
position error.
New style errors.
New style test passing.
Sort.
Cleanup.
Additional accuracy level.