Resolve "Check propagation of required branch names from within algorithms"

Release notes

Fixed Tree branches only used from within algorithms (specifically: TQAnalysisAlgorithm, used for, e.g., unfolding response histograms) not being enabled. If your custom TQAlgorithm uses certain branches (e.g. via Observables), make sure to override (implement) the new TQAlgorithm::getListOfBranches() in your derived class. This would likely be a few lines analogous to TQCut::getListOfBranches().

Details

Closes #352 (closed)