Check continues beam example script

[grzanka]

Take a look at https://github.com/jbrage/IonTracks/blob/master/hadrons/example_continuous_beam.py

• check if the script can be executed correctly after merging Added test cases generator for ks_initial_IonTracks #22
• adjust imports if needed
• add an test suite in test directory covering the parameters used in the continues beam script

[grzanka]

@retkiewi take a look