1) AliCaloTrackReader: Possibility to open a second input file with events, when...

1) AliCaloTrackReader: Possibility to open a second input file with events, when reading AODs
                                      Possiblity to access Stack or MCParticle
                                      Select tracks depending on track status
                                      Replaced the TRefArrays by TObjArrays
                                      Bug, ESD tracks were being set in arrays twice.
2) AliAODPWG4Particle: New data member for b tagging added (Mark Heinz)
3) AliMCAnalysisUtils::CheckOrigin: Split in 2 for stack or AODMCParticle reading
                                                          Returns bitmap, not a simple tag.
4) Minor code violations corrected