Merge branch '41-implement-simple-homogenous-atmosphere-model'

CMakeLists.txt

Documentation/Examples/cascade_example.cc

Environment/CMakeLists.txt

Environment/Environment.h

Environment/HomogeneousMedium.h

Environment/IMediumModel.h

Environment/NuclearComposition.h

Environment/VolumeTreeNode.h

Environment/testEnvironment.cc

Framework/Cascade/Cascade.h

Framework/Cascade/testCascade.cc

Framework/Geometry/BaseTrajectory.h

Framework/Geometry/CMakeLists.txt

Framework/Geometry/Helix.h

Framework/Geometry/Line.h

Framework/Geometry/Sphere.h

Framework/Geometry/Trajectory.h

Framework/Geometry/Vector.h

Framework/Geometry/Volume.h

Framework/Geometry/testGeometry.cc