float precision test
Rutherford Scattering numerical and analytical result comparison

ToDo: -Explain and eliminate all weird errors for example to phi(r).
-Already eliminated one deviation resulting from the prerequsite of a
 inifinetly far away initial particle by using the analytical result.
 Although choosing bigger x0 would also have worked. But that would render
 dt nearly useless. A variable step size would combine both pros.
-There seems to be an offset on the angle in before and after the minimal
 distance to the center particle
-The deviation to the all in all scattering angle is to big!
-implement two particle scattering, not one particle at fixed potential
  -> use center of mass or momentum
-relativistic scattering? -> potential change, time dilation, spacial
   constraction, increasing mass, ?
-Energy is not always constant! -> implement Verlet/Leapfrog