Modernize TrackExtrapolators
- declare Boost headers to be 'system' headers
- prefer std::abs over fabs
- prefer Gaudi::Property
- add final
- prefer implicit (compiler generated) destructors
- do not cache msgLevel(MSG::DEBUG)
- modernize TrackRungeKuttaExtrapolator
- create dedicated type to select Butcher Tableaux as property
- group various magic numbers in explicit Butcher Tableaux
- use boost::variant to keep track of various Tableaux
- pass the above variant to extrapolate
- make templated evaluateRKStep, evaluateRKStepJacobian and instantiated it for the various Butcher Tableaux
- according to cachegrind, this uses 5% less cycles...