Actually the debug package contains also a complete reimplementation of
the CaloParticle logic fully based on the BGL that greatly simplify the
extremely complex logic of the currently used CaloTruthAccumulator. The
implementation is not yet final but gives already identical results if
compared with the regularly produced CaloParticles.

Full recursion and creation of CaloParticles.

Add more histograms to monitor CaloParticles and monitor more kind of
particles based on their pdgId.

Few particles  are linked still to vertex 0 but are separate from the
main vertex graph. This will recover them and promote them to be
CaloParticles if them or any of their children leave hits in the
configured calorimeters.

Every CaloParticle is linked to the first stable particle originating
the cascade of particles that left hits in the calorimeters: that
stable particle is not included as a simCluster (unless it itself left
hits in the calorimiters). Additional code has been added to find a
matching track based on the trackId linked to the CaloParticle itself,
not to the associated simClusters. The most important clients affected
by this change are electrons.