#32 Automatic stopping criterion

[Vukics, András]

This feature used to be in DO_Display before trajectory-state serialization was introduced.

Now it should be integrated into trajectory::run to make it really general, and the corresponding parameter added to parsRun.

[Vukics, András]

The corresponding parameter should simply be the number of repeated identical displays within a given precision, which could be the same epsRel used by the ODE stepper. (?)

This means that ParsRun should have a common base with ParsEvolved containing epsRel.

[Vukics, András]

Implemented on 3ecefcf1e.