Added cmd line arguments --eventParameters, --runNumberOffset and --eventNumberOffset to steer lcio output parameters

Adding the helper to allow reading an MCParticle collection with an arbitrary name

whitespace to emulate the output from DD4hep
Solves #56

  - to activate run ddsim with:
     --part.enableDetailedHitsAndParticleInfo

 - add option to enable debug output actions for hits from Markus

Add Helper Input and GuineaPig for further expansions in the future

Set on the command line with

   --guineapig.particlesPerEvent=123

or in the steering file

   SIM.guineapig.particlesPerEvent=123

This reverts commit 70feca4742a0721bdbe7197de1a33eb878a63799.

as we are now potentially changing the random seed we need to initialize it before the output file, because we write the variables to the outputfile at this point

Add option to enable eventSeed plugin
Add possibility to create switches automatically, this does not allow 'choice' so we need to if/else the whole function call add_argument

Need to return the value
Kept DDg4ParticleGun from working

Cannot use PrimaryHandler together with either of these (particles are created twice)
Thanks to S.Lukic for pointing out the problem

Move consistency checks to separate function for better readability

DDSim: Add functionality to enable geant4gun and geant4 particle general source. Needs DD4hep Revision 2128

Add example macro file to use gun or general particle source

Do not print error messages when dumping SteeringFile or parameters
Fix crash when dumping steeringfile

DDSim: Add logic to add help for non-property helper variables, add logic to add choices for all helper options

Add control over distributions
if a distribution is set activate isotrop
if isotrop is activated use uniform by default

Move set up gun function to Helper/Gun, keeps functionality closer together

previously only the main variable values were overwritten, now dumpSteeringFile and dumpParameters will also display the proper value

Add white line before documentation block for better readability

Otherwise error for unknown function, reported by Marko,
Copied fix from DD4hep::DDG4.py
change is compatible with root5

If used isotropic is mandatory so we turn it on in  setup
Note different capitalisations for options,
keeping lower case starting char for ddsim options

needs dd4hep revision 2071