Added one 'Geant4ScintillatorCalorimeterAction' into DDG4 plugins Geant4SDActions for  scintillator to take Geant4 BirksLaw effect as sensitive detector active layer.

Create stringstream to avoid changing output format for cout

No code changes. Common code formatting removing tabs, replacing with spaces (tab-size=-2) + emacs reformatting.

Improved version of MC particle handler, fix calorimeter hit aggregation with multiple contributions

Hopefully I got the assemblies right now. Assembly test added in examples/ClientTests. Please see also doc/release.notes