Need better reporting of the "apocalypse" crash

[pleroy]

#1114 has an example where a customized solar system triggers the crash. While there is not much that we can do to stabilize customized solar systems, we should do a better job of reporting the problem. Something like "The trajectory of body Foo had a quirk with its speed jumping from ... to ... This probably means that you are using a customized solar system and that this solar system is unstable in the presence of N-body gravitation."

The tricky parts is to propagate the error from ContinuousTrajectory all the way to the UI.

[pleroy]

Implemented in C# in #1140 but now we cannot reproduce it anymore.