Unify step handling
Fully reorganize save rate optimization:
- consider radiation pressure for the save_factor calculation
- change from a reduction of n to an increase of the stepcount (now SpiceDouble floating_stepcount)
- remove upper limit where it is simply 1
- change formula to a more steep increase but a limit of maximum of additional steps (currently 40 saves per one non-optimized save)
- remove bug that only considers planets when they reduce the acceleration