[Orekit Developers] Converting some JTest code into codified Sim code

[<w.grossman@ieee.org>]

Parts of the Jtest code necessarily create input/output test vectors to VERIFY
the OreKit code.  In many cases (all?), these test sets are high-fidelity
sufficient to verify the high-fidelity aspects of the OreKit code.

If validated, as much of the test vector generation code likely is, this code
can be the basis for a simulator used for code development.

Issues of validity and incestuous testing are ever-present and need to be
addressed.  Such is life in this business.

Anyone interested in helping the effort?