Modernize Track Likelihood
- avoid redundant copies & loops
- add ITrackFunctor in order to be able to deprecate the use of ITrackManipulator -- ITrackFunctor just computes some observable (which has a float value) and returns it instead of modifying the track it is given
- Make TrackLikelihood inherit from ITrackFunctor instead of ITrackManipulator, and make it const-correct
- TrackAddLikelihood now calls ITrackFunctor to obtain values, and then it forwards those value to Track::setLikelihood
- Prefer Gaudi::Property
Edited by Marco Cattaneo