getDescription for ModuleList
improve python pretty print
Observer deactivates by default (as user would expect for 1D simulations)
SourcePosition: simple constructor for 1D
getDescription and new constructors for Candidate and ParticleState
crpropa.i use __repr__ ( = __str__)
explicitly include Units.h, ParticleID.h ...
allow massNumber for neutron = 2112
descriptions for all ObserverFeatures
descriptions and pretty print for all SourceFeatures